Is there any government that is even considering adopting bitcoin as legal tender that is also hesitant because of energy consumption concerns? I seriously doubt it.
We've always known that governments don't like bitcoin because it is decentralized which means they can never control it, print it out of thin air, censor people's transactions, and stuff like that. Everything else including environmental impact, energy consumption, etc. is just an excuse because if they announced the real reason ("we [the gov.] can't control bitcoin so we fight it") it would lead to mass adoption in a blinking of an eye

As for the "waste to energy" idea, it is already being done in a lot of developed countries. The electricity it produces is not enough for mining farms though specially since there are easier and "cleaner" way of getting that electricity like something as simple as solar panels.

In theory, in reality, a money pit!
That thing has burned more money than waste, had to be bailed out 3 times already in a decade.

A Danish fiasco: the Copenhagen incineration plant
https://zerowasteeurope.eu/2019/11/copenhagen-incineration-plant/

With recycling taking more and more trash out of the dumps in economically feasible processes and Europe emphasizing more on recycling than just burning it for energy large plants make no sense anymore, and smaller ones make sense are not going to be running 24/7 but in snatches to provide energy during peak consumption times.

There's more than enough industrial heat "left over" for that already, but it's not that easy to use for heating on a large scale.

most people put their paper/card stuff in recycling bins.. where the general waste is the more hazardous stuff that cant be recycled. incinerating this stuff will cause poisonous fumes if just dumped into a fire.. or excess costs to sift through the trash to find the safe materials to burn

its not cost effective

This is a very good idea of changing the waste products into energy but here I am a little bit suspicious about the government. Is the government not adopting Bitcoin mining due to high energy requirements? I don't think so because bitĉoin is based on blockchain and is decentralized which the govt does not want. There are many countries that allow and support bitcoins but also some other states that ban bitcoin not on the reason of low energy but on the basis of its decentralized nature.
But yeah economically and environmentally it's a good plan to reduce the waste in your cities and and change it into energy. This could lessen the greenhouse effect and also provide new job opportunities for the maintenance of the plant and give good revenue to the govt. Also, these plants can less the cost of energy for Bitcoin mining as it requires a huge electricity which is high in cost if this plant gives the required energy to Bitcoin mining it will cost less as it is produced from waste. So in my view its a good initiatve for both Bitcoin mining and for the state.