First of all I want to preface my comment with the disclaimer that proof of stake is nonsense in many ways (vulnerable to coordinated bribery attacks - we don't know how to coordinate well enough to execute them yet but the math checks out, also plutocracy..)

However it is a pretty expedient way to get something out the door fast (it's literally the simplest form of anti-sybil you can make and a cryptocurrency is anti-sybil + consensus).

So given that we accept proof of stake as a good way to prototype different approaches then a cryptocurrency that meets you criteria is the avalanche cryptocurrency (AVAX).

The way it works is via "stochastic gossip", whenever there is a conflict (double spend or some kind of decision problem where a node is unsure what is reality) then a consensus "game" is started. The way the game works is that you sample some reasonable sample of peers in the network (say 30-40 peers) and ask them "is A or B the legal state of the world?", now an honest participant will naively believe whatever the majority decision is.

Due to how stochastic probability stuff works the network will converge if you repeat this game sufficiently often. The idea is that if the initial state is 60% think A is the correct transaction then after a few rounds (they do 17 rounds which is overkill, you get like nine nines of probability or something) the whole network will have come to that conclusion (each time you run a round of the game the majority will _probably_ grow, eventually only the byzantine nodes are still saying B and if they are not the majority then all conflicts are solved).

Now bear in mind, there are some drawbacks, if someone is stubborn or does the opposite of what they should then maybe they can have some outsized influence, but in general this works pretty well and you can have a _lot_ of nodes participate in the network (much much more than in nakomoto consensus due to the different nature of the consensus mechanism). Furthermore you get finality in 3 seconds (even with the 17 rounds) so that is also quite nice (if you want to reach VISA level of transactions...

A validator in the avalanche network doesn't need some crazy hardware either.. a raspberry pi is fine, the limitation is you need the machine to be online 80% of the time they stake for.

That is one solution. There are others. For example amoveo, which is proof of work BUT it solves the second order byzantine fault tolerance problem (also known as the "oracle problem") which means that you can account for externalities (like energy usage) and throttle the mining rewards or adjust parameters in response.

I am working on a very raw but next-gen project myself, it's called datalisp (I wrote a very bad "whitepaper" in one sitting a couple of weeks ago... it's at datalisp.is - there is a telegram channel.. we're trying to figure out a lot of hard problems and we'd rather show than tell so if the whitepaper is somewhat up your alley then there is a lot more elaborate stuff happening in the channel).

The point of what I am saying is: if we want to kill bitcoin then the simplest way is to just make a better solution and change the narrative around the whole scene. I hate all this nonsense proof of stake ponzi nonsense, if a cryptocurrency is well designed then there is no advantage from being an early adopter (i.e. we solve byzantine fault tolerance _AND_ tragedy of the commons).

Please don't shit all over those of us who want to solve hard problems in a good way just because there's a bunch of assholes trying to get rich quick.