It is definitely an interesting topic. Not just in relation to cryptocurrencies but by itself. While, we have all had a taste of the weirdness of quantum phenomena, real applications of quantum, although ubiquitous, still feel esoteric to most people. The paradigm of quantum computing is actually following the idea of solving problems in quantum methods rather than classical methods. For example, programming evolved before evolution of computing hardware from William Shockley's humble BJT.

Hence, anyone looking to understand quantum computing will first need to understand the theoretical framework of quantum "software". For example, in Neumann Logic, the state of a "0' and a '1', allows you to express Gates==>Memory==>Adders==>Calculation==>Program flow and so on. Then computer scientists use algorithms to express solutions to real world problems in ways that a computer can understand.

So when someone talks about Quantum computing, the question i ask myself is what exactly changes if instead of just a "0'" and a "1", you have access to superposed values, in-betwee values. What does that even mean? How does it make algorithm's faster? Those are all hugely interesting questions to dip your beak into.

Umm, "integrate quantum mechanics into mining software" sounds incompatible. The software will remain software. Maybe they'll call it quantum software.

We will not see big adoption of quantum computers in the near future. I dont think that big companies like google will use QC to break crypto

In 70s, it seemed obvious that in a couple of decades people would go to Mars on a regular basis, and perhaps there would even be tours for tourists to other planets. It's been 50 years, and humans did not get any of this done. What I'm trying to say is that quantum computers might become another case of something that seems so close right now, but would not get any closer in 50 years or maybe ever. There've been developments, there've been speculations, but clearly humanity is still quite far from figuring out how to build one and whether it's even possible. So cryptocurrencies seem quite safe for now. And even though it's the case, there are already cryptos which brand themselves as 'quantum-resistant'. Maybe it's as fake as computers which currently brand themselves as 'quantum computers', I am not sure, but I think there are more pressing concerns than quantum computers when it comes to cryptos.

It´s a topic that is relevant in a few years but developers need to start to take in in consideration when building new apps already. Even Deloitte posted an interesting article about it https://www2.deloitte.com/nl/nl/pages/innovatie/artikelen/quantum-computers-and-the-bitcoin-blockchain.html

However, development must happen step by step and there are many current issues that ask to be solved before that. First, some standardization would be good, so would be easy and fast interoperabilty...

ECDSA is the correct acronym. Bitcoin also uses hash functions for much more than just creating blocks. Turning your seed phrase in to a master private key, deriving all your subsequent private keys, and turning public keys in to addresses, all use a hash function.

No there isn't. Bitcoin could implement quantum resistant signatures via a soft fork, which would create a new address type just like the SegWit soft fork did. This new address would use quantum resistant signatures, and so everyone would simply create one or more of these new addresses and send their coins to them.

quantum mechanics vs quantum computing

mechanics is about understanding something at the more accurate nano/pico level of the smaller pieces inside the pieces known at the macro/micro level

for instance what we deem ice as a solid object at the macrolevel
is water particles not moving and compressed together at the micro level
is h2o molecules at the nano level
and is energy waves compressed together to form barriers of resistance/interference at the pico level

understanding things more accurately at smaller levels allows not only more accurate results. but also allows tuning devices to be more precise to even fit more devices into a smaller area without losing quality

things like voltage
at the macro level of a 0.1v accuracy rating. a voltage of 0.0924v would get rounded up to 0.1v
its not saying the voltage at any given split second is both 0.0924 and 0.1 at the same time. its just the observation method affects what the result is because the observation method is not accurate.
also a volt meter might actually use 0.0004 to measure and round. so although the voltage is 0.0924
when measuring it then a 4 decimal accuracy voltmeter would read it as 0.0920 yet as i said its actually 0.0924 if you can account for the dip due to the measuring method.
again its not that the actual voltage is both 0.0920 and 0.0924. its about understanding all the things involved to get a better more accurate result.
..
super positioning is not some new universe cross reality multiple position theory. its at the macro level vs micro level in terns of computing just accuracy where the measuring/observation device is interpretting and rounding it off to something it can recognise
say we play with 0 or 1 volt.. due to inteference nothing is absolute 0 or absolute 1. so when no power is on the cable might be picking up 0.2v of interference from neighbouring cables.
and when charging 1v through the cable it loses 0.2
1.0
0.8                    \/\/\/\/\/\/\/\
0.6                    |
0.4                    |
0.2\/\/\/\/\/\/\/\/
0.0
so macro would round it as 0 or 1...
so micro would round it as
0.2 0 0.2 0 0.2 0 0.2 0 0.2 0 0.2 0 0.2 0 0.8 1 0.8 1 0.8 1 0.8 1 0.8 1 0.8 1 0.8 1 0.8 1
same voltage in both cases.. but accuracy of 2 different meters of
0-1v over 2 seconds.
vs
decimal accuracy at 20x10^ths of a second(2seconds)

and its this that QC computers are playing with the most
not only more acurate measuring but also cancelling out the interference so that instead of 2 gates 0-1  current generation QC is playing with 4 gates 0-1-2-3
0.30
0.25^{\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/}
0.20                    
0.15_{\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/}
0.10                    
0.05^{\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/}
0.00_{\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/}

where the gaps in between are precively chosen so that they are at their different levels of energy not going to interfer or be confused/rounded to the next options

imagine it like going from a volt meter that can only measure 0.0v as binary0 and 0.1v as binary one
and then in the same size transister. QC can now measure 2 decimal
so 0.00v=0        0.05v=1        0.13v=2    0.26c=3

now instead of base 2 math they can have base 4 with each transister being upto 4 instead of 2
so it allows Hex(base 16) to be stored in 2transisters instead of 4 transisters

do it with less energy too as they are now using microvolts instead if milivolts

this 4 positions allows for more options
instead of just north/south true/false yes/no and then getting confused if the voltage fluctuates to decide to round something in the middle as a north or south, yes or no they can be more precise and call it east and west, sometimes/mosttimes, left/right

so now they are working in 3d vectors much faster then 2d vectors.
this makes elliptic curve math much faster as it can interpret updown left right faster than trying to get binarys limited one transister: up down and a separate transister: left right to figure out vectors

..
anyway back to mechanics.
by knowing things at the pico level like everything is just a wave ultimately.. depending on how many waves and their frequency and strength factor into how much interference/resistance. they can find new ways of deciding what 'materials' to use that have least interference set on them so that they can make smaller transisters and not have it over heat due to density of multiple transisters
they can also work out what interference things are still occurring so they can math them out of the equation of measuring the value the transister holds or combat the interference with their own wave generation to cancel it out(noise cancelling headphone idea)

right now they want a QC computer at below freezing because at that temperature no heat is interfering with their results. so if they take a regular reading of something they know the result before passing it through the QC computers. and then try it again at higher temperatures. they can work out what waves are appearing to then design wave cancelling methods. or just mathematically substitute it out. by predicting how the interference may change a result and correcting that result in lieu of the interference
 
hoping slowly they can get to a point of still having accurate readings but at a more fashionable temperature that people can reproduce at home.
this side of things will take along time

meanwhile at the most accurate resul temperatures. doing other science
they can play around with this 3d dimension mapping instead of 2 dimensions. and create new algorythms and get results of complex 3d puzzles that 2d binary just cant really handle

its ability to solve 2d binary problems is just efficiency. because a binary problem with a binary solution has to have binary logic. and as such is just 2x efficiency
but vectors and eliptic curves are not binary problems. they are 3d vector problems. which QC can handle many many times faster.

but with that said.
bitcoins ECDSA is a still not going to be a 2 second brute force

imagine it this way if you were to try brute forcing all 256bit possibilities
115792089237316000000000000000000000000000000000000000000000000000000000000000. 00
at a pace of 1billion tries a second. would take you this many years
/1bill/60/60/24/365=
3,671,743,063,080,800,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
in binary
and still many thousands of years in quantum

all the other talk about alternate dimensions and teleportation across the planet and other stuff is more done to fool people into thinking its al mysterious magic so the guys playing with it can get ahead and master it without much competition..

the 'spooky stuff' is interesting for other things. but in QC its not what they are needingusing
take the spooky about affect something one side and the equal opposit reaction happens at the other instantly
its not spooky
they just want you to think if you have a bath tub of water and splash at one side. usually it takes a few seconds for the ripple to reach the other side. and they found new ways to make the water move the other side instantly.
the trick hear is not to think about the water on one side as lots of individual parts that if you tap one part its partner on other side gets it.. but instead everything around is all connected. and if you tilt the bathtub you instantly notice the water is at a deeper water line one one side and shallower at the other.. no delay
..
like the ocean tide when the tide is in at one side of the planet it is out at the other side.
its not the single lapping wave being in 2 places where the wave at one end is in direct communication with a wave at the other end telling it to do the exact opposite. its the fact that the whole volume of water acts as one. 'object'
same with light.
wave particles in a beam of light at macro/micro level are treated as lots of little 'photons' but at the pico level you see they are all joined together by waves not normally seen at macro/micro. so when you think your splitting a beam in half and only affecting one side. thinking there is no way it is able to reflect back and then down the other directions.. what your not realising is the interference is affecting the non visible wave at pico level which then affects the visible wave at the other side
EG less white light interferes with the pico level gamma wave thus the gamma wave on the other side reacts causing it to affect the white light spectrum on its end
exciting stuff..
but this interference and stuff is what QC computers want to try limiting and separating so that they can have more precise readings to allow more options in a smaller confined space.

other exciting revelations
take splitting atom. is not the image if cutting an apple in half to see the core.
its about neutralising the energy waves that form the 'shell' of an atom so they can utilise the gamma wave inside that links the shell waves together and holds them together normally

its actually some fun stuff once you get your mind around it and debunk the sci fi magic/universe buzzwords used to keep only a select few ahead of the competitive edge

If quantum computers can do all of the above then we already have cryptocurrencies that have technology against quantum computers, in theory so.
As for the mining problem, we cannot change the POW technology. We can only change the form of crypto mining.

From what I can find quantum computers have two major issues, that are being worked on and will diminish, but slowly :

- the number of qbits is very limited, and increasing it is a challenge due to errors being generated

- developing algorithms for them is something new that people aren't good at, yet

If we look at the development of classical computers, many of the concepts and algorithms were invented by mathematicians/engineers decades before they could be implemented in an actual machine. Things advance more rapidly today on the hardware front, but I'm not sure we make much more good mathematicians these days than in the past.