MistyMC is a long term 100 percent vanilla SMP that has been running for around 8 months and it is meant to stick around with no resets.
Players can join on Java and Bedrock on the most recent versions so it is easy to bring friends from either side.
The community is a big tight Discord group and the vibe is to make friends and chill or jump into a new Minecraft phase and form a nation.
There is also a live map you can use to check out the world while people play.
