I found a survival server running on 1.21.10 and it feels like a mostly vanilla SMP with a clean setup.
The big twist is custom structures placed around the world so exploring does not get boring and you can stumble into cool stuff while roaming.
It also supports joining from multiple Minecraft versions because it uses ViaVersion and ViaBackwards so you do not have to be exactly on 1.21.10.
The community is small and still growing and the whole place is meant for building exploring or just chilling without feeling like another number. Performance is also said to be stable.
