I found a Minecraft Java server called 2x2y that is going for true anarchy on 1.21.11. It is the kind of place where there are no rules and you can do whatever you want.
People can fight raid and grief and nobody is there to stop it. You can try to build a base or hunt for other players and see how long you last.
It also says it is meant for a mature crowd with 18 plus players welcome. The server runs on Folia and it just released today.
