I found a long term vanilla server that started about eight months ago and it is meant to stay stable with no resets.
It supports both Java and Bedrock and it runs on the latest versions so you can hop on with whatever you play.
The community feels close and active with a lively Discord where people talk and plan stuff.
You can chill and build or bring your friends and do that classic two week phase and try to build a nation and make new friends.
Hemisphere SMP is a semi vanilla survival server that has been running on the same world for ten years with zero resets. It is inspired by Hermitcraft and it sticks close to real vanilla gameplay.
The server runs on Java 1.21.11 Fabric and it uses quality of life stuff like proximity voice chat plus custom audio discs. It also has Armor Statues and More Mob Heads and Wandering Trades tweaks while still keeping vanilla mechanics. There is no teleporting and no overpowered plugins and no weird modded blocks.
I saw that the community does a lot of shared projects like a minigame district with game nights and themed build districts that keep growing. There is also a big custom Decked Out style game that the players made.
You have to join the Discord and apply before you get full access and whitelisting usually takes under a day.
MistyMC is a long term 100 percent vanilla SMP that has been running for around six months. It is a no reset world so your builds and progress are meant to stick around.
The server lets Java and Bedrock players play together on the most recent versions. The community is pretty tight and active on Discord and it seems like a good place to make friends.
People join to chill with others or bring their buddies for that two week Minecraft phase. Some players also like forming nations and just living the SMP life.
There is also a Bluemap so you can look at the world map outside the game.