I found a self hosted Vanilla SMP that is all about normal survival on Java 1.21.10.
It has a world map you can use and besides that it stays completely vanilla.
They are trying to keep it as a small community and they also want operators to help it grow. It runs on an old desktop that has been up for a long time so it is meant to stay online.
Gavins Vanilla SMP Small Community
GG.MINEWIND.NET New Server IPFresh Vanilla World Just Started
I found a brand new Minecraft server that is just about playing the game.
It is vanilla style with no major mods or plugins. You can join up and just chill and play like normal.GG.MINEWIND.NET New Server IP