Over the next decade, Bitcoin aims to handle more transactions efficiently and reduce its environmental impact, keeping its commitment to decentralization and security.
There will be the help of layer-2 solutions and adopting greener mining technologies.
These steps are expected to make Bitcoin, more sustainable, and securely future-proof. Just my 2 cents.

bitcoin mining devices do not see nor care whats inside a block.. an asic just hashes a hash..
a block can be empty or hold thousands of transactions, and neither end affects the mining chore/work/function

so transaction scaling is not going to cause environmental disaster

as for the separate issue of speaking about only the mining function done by asics
well compared to hashes per second of CPU, asics have already made advances in innovated methods to achieve more hashes for less power per hash

as for speaking about renewable sources of energy. this is not a issue of bitcoins cause, but an issue of a countries own power companies that need to change their own business models per power company/power plant. infact its electric vehicles making energy demands at random times of day in bursts of 70kwh in 20minutes that will cause more power impacts, compared to bitcoins predictable power utilisation

bitcoin miners have a predictable rate of usage
EG 24/7 3.5kwh at x asics per location.. which can be calculated and predicted for the 2 year lifespan of those asics
and so asic farms can have payment contracts drawn to buy power in allotments to cover that 2 year period

ev cars however use 70kw+ per full battery but charge at random times of day/week in short sharp surges. unpredictably

last thing to note. there are less asics on the planet than there are EV cars. so it will be the car industry that will impact power demand, power surge and brown out risk possibilities, so they need to get involved more in the innovation of power supply companies

as for bitcoin innovations for bitcoiners benefit
bitcoins never leave the bitcoin network,, FACT
so silly idea's that innovating bitcoin involves tricks to get people to abandon using the bitcoin network as being innovative, are laughable
subnetworks that dont use blockchains are old tech, old idea's not new (the cypherpunks were playing with those old idea's even before bitcoins invention)

bitcoin network needs to scale. and by this i do not mean the idiot echo chamber narrative of bitcoin being a dystopian one world currency needing to cover ~300k tx a second for the entire worlds currency usage of all currencies in one

the reality is much more scalable..
things like code(which bitcoin is) that:

* formulates ways to punish only the bloating spam creators. to cause them to not be using as much space per block, to then allow more genuine transactions to confirm sooner by being added into the space that spammers/bloaters took up

*creates transactions that are leaner than the current average of 1kb (4k tx/4mb block=1kb per tx average). transactions that can be less than a quarter of current averages can multiply the amount per block allowed

*re-utilising the 4mb space as true 4mb for the main tx data, without the metadata junk of the 1mb base:3mb cludgy miscount segregation
this also can increase the transaction count

*and then the blocksize increase, does not need to leap to obsurd amounts narrated by idiots. but instead progressively grow, this can be done without dev politics need of involvement deciding how much and when, but instead using code to read blockdata and at certain milestones all nodes react and change the amounts allowed...  (much like hashrate difficulty does not need dev political input per fortnight, the nodes work it out themselves via blockdata)

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the current lineup of subnetworks fail many tests of security, autonomy, meeting their objectives,
there will be future subnetworks yet to be made from scratch that will fill niche needs of temporary services.. but without the presumption that everyone should abandon using bitcoin and be locked into those niche subnetworks for long periods

The issue with transaction charges, maybe later it implementation of the increase on block size will not be a threat anymore to bitcoin users from having an increasing transaction fee rate, people want to experience the lowest and possible least rate for making bitcoin transactions and this will be their utmost desire in using this decentralized currency when they found out that its the least or one of the least that has lower cost of making transactions in cryptocurrency.

Hopefully we would finally solve the problem of transaction fees and congested mempool. I think that if tech were developed to reduce transaction fees, we could truly use bitcoin as a method of payment and adaptation will be way underway.

Another thing would be figuring out how to minimize the energy being used by bitcoin. I personally do not think bitcoin is responsible for most of carbon emissions however it would still be helpful to the environment to mitigate the impact of climate change as much as we can.

Proof of stake (POS), layer2, sidechain...? How can you call these technologies that will make bitcoin faster and better while still being decentralized and secure? I sincerely ask, do you know what the concept of POS is?

In terms of innovation to make bitcoin better, we don't have too many solutions so far. Besides applying LN to reduce transaction fees, expanding the blockchain or reducing energy use, we still don't have any technology that can solve it. We are all waiting and hoping that the developers will find some solution soon.

lightning is just a shoddy sandbox experiment that doesnt meet promises and has many flaws and bugs
other subnetworks will be made later(from scratch) learning from LN mistakes. offering niche services
BUT
bitcoin network is the bitcoin network, bitcoin stays on the bitcoin network.. thinking everyone should lock up their btc and then abandon bitcoin utility pretending these subnetworks "improve bitcoin" is like saying lock up your gold.. use bank promissory notes/credit cards to avoid using debit cards/assets.. under the guise of 'to improve the debit card system'..(but doesnt improve it)
 
.. in actual fact is LN's function is to lock your real assets up and then use debt/credit(unsettled iou's as debt/credit depending on which side of the channel value you sit on) on another system and abandon using a real assets movements, to play with iou units on another system and settle up when your balance is zero and need to hand over(close channel to utxo confirm transfer of) real assets to then lock up a new set of assets to then play with iou balance debt/credit again, until you settle up again

yes there will be niches for these debt/credit facilities of swapping unsettled debt.. and borrowing partners/routers credit balance.. but lets not just push for bitcoin to become a worse offering compared to fiat..

there are ways to disable the opened opcodes that allow unchecked junk to pass into blocks

there are ways to open up the 1mb base:3mb segregation to be a unified 4mb space for real tx data
which those two things alone will allow more transactions to utilise the 4mb space that devs dont have issues with the network filling per block
and even the tx formats where signatures/sigscripts are at end of a tx can still function (so no fear fud that it breaks "segwit" "taproot" transaction functions)

there are ways to make transactions even more leaner than the current 1kb average tx (4k tx in 4mb space=1kb per tx)

and there are ways(if cultish groups stop their REKT campaigns of other brands operating on the network offering proposals) can offer other brands with proposals of these things and also options of blocksize increases without needing to wait and be patient for core dev political human trust/decisions

At the moment, L2 networks of BTC are in great hype, there are bundles of new projects in the market that allow staking, and other types of implementations even Dapps too, for example, galileo, particle network, satoshiVM, etc, these types of projects are broadening the vision of people that they have set for the BTC. Like who would have thought we can do staking in BTC and can use BTC for dapps. And who knows what is coming next?

Besides this, there are other updates on the network level, like the V27 update where they will try to eliminate the inscription feature or error (whatever you consider it). That's what I knew, I hope to know more in this thread, BTW its a good one.