I found a Fabric SMP that is trying to fix that problem where you join and everyone is already stacked and the admins are gone. This one is meant to be a fresh start so you are not showing up late.
It is a 1.21.11 Fabric semi anarchy server with light mods. It is mostly small quality of life stuff so it stays smooth and the rest is just part of the game.
The world is still new so there are no huge empires yet and no untouchable players. There are places to explore and loot to restore plus secrets hidden around.
They also run in game rewards and community events. There are invite rewards too and they say they are actively developing it for the long term.
