PoS is a POS. "Energy efficient" alternatives are flawed. PoW is secure and maintains decentralization unlike PoS.

"Wealth is commonly centralized. And with PoS it is rule by the elite rich. There are many ways in which wealth is or can be centralized. Such as early adapters, thieves who steal from others by force (this also includes organizations like the U.S. government which has stolen at minimum, hundreds of thousands of bitcoins from people who were never convicted of any crimes), exchanges which hold a majority of balances, custodial services, banks offering interest to people who deposit their coins with them. When it is something scarce like a digital token of fixed amount, it is hard to reclaim power from those who wield it, especially if they do not ever give up their tokens. At least with PoW, anyone can take part even if the machines needed to mine are expensive. PoS also promotes exponential growth of centralization of power in a loop. More wealth = more power = more wealth, and it repeats"

source: https://mwica.institute/blog/truth-on-bitcoins-energy.html

I am not trying to shill any website. I would rather post the entire rant here but reddit has a limit on characters. So I posted one relevant section here on the issues of "energy efficient alternatives" to Bitcoin. There are many issues with PoS, and many reasons why the claims of "Bitcoin has an energy problem" is incorrect.