PlayCraft is a new Java survival SMP that is aiming for active long term players and it is adults only 18+.
It runs on hard difficulty and it is semi vanilla so it stays close to the normal game. The world has been running for about one month. Achievements are enabled and one player sleep is turned on.
The rules are simple. No griefing no stealing no cheating. PvP only happens if both players agree.
I found a small Minecraft server that is meant for people who want to stay on one world for a long time. The map has been up for about 4 months and the goal is not to become huge. It feels more like a place where you build and keep coming back.
It runs on version 1.21.11 and the world border is 1m by 1m. Player count is usually low like 0 to 9 online. It is hosted on dedicated hardware in Germany and the TPS is around 20 most of the time.
Gameplay is semi vanilla with a few convenience features like TPA and homes. Those homes are earned through voting. Dupes are patched and the anticheat blocks non vanilla movement and x ray.