I do not think that any cryptocurrency that will be backed by the government or accepted by the government will have any form of proof of work because, in short, it gives individuals a greater degree of decentralization, and competitors can intervene if they do not like the government's decisions.
Therefore, proof of stake is the future if we want to see *environmentally friendly currencies* and not generate clean energies for crypto mining.
Although countries and governments hesitate to promote Bitcoin and crypto, they know the power of crypto and they cannot deny it. Also, just as nowadays, if a country has high dollar reserves with them, they are considered to be a developed nation, similarly in future country strength will be determined by their bitcoin reserves.
Recently i read a news where
Bhutan is silently mining Bitcoin for years since BTC was $5,000. We do not know how much bitcoin this small country has accumulated but we must know where the world is heading next. When small countries are serious in getting bitcoin, you can imagine the developed countries will be more concerned to get bitcoin before it's too late, or too expensive. There will be a race to get more and more bitcoin and bitcoins are not just enough for everyone due to their limited supply.