Rosedalean SMP is a Java server on 1.21.11 that feels like vanilla but with extra stuff added in. It is made for both casual players and hardcore players so you can play how you want.
The server has an application system to help keep trolls out. People run community events and there are factions you can join or even start yourself.
It uses add ons so you do not need to download any mods. It also has simple voice chat and a world map you can look at to see what the explored world looks like. There is a ticket system if you need help and they do weekly game nights. They also listen to suggestions and try to improve the server with the community.