I found Xapros SMP and it is a chill vanilla Minecraft server for adults.
The world is meant to be long term and it started in January 2025. They say there will be no resets so it is good for big builds that take forever.
The community is 18 plus and people play from lots of places around the world so someone is usually on. Peak time looks busy with around 20 to 25 players online.
It runs on Fabric so redstone and farms should act like singleplayer vanilla. They also added BlazeandCave advancements if you want more goals.
There are no land claims but griefing and stealing are not allowed. There is a ledger inspect command for checking what happened.
Spawn is built up and there is a diamond shopping area for player trading. Travel is easier with Nether ice boat highways. There is also a Bluemap and there is no world border so you can go as far as you want.
It is free to play with no ranks and no donation perks.
