I found a long term survival world that stays vanilla and plays on hard difficulty. It is meant to feel calm and actually multiplayer even when a lot of people are on.
There are no land claims and no locked chests so it feels more immersive and shared. PvP only happens if both people agree like friendly duels.
They say no theft and no griefing. They also use tools that can restore builds so the world stays safe.
There are no payments or donations or perks. You can join and explore right away but to break blocks and fully interact you have to read the rules in game and follow the getting started steps.
