I found this Minecraft server called TryToChill Network and it looks pretty fun. It is a Java server and it works from version 1.7.2 all the way up to 1.21.11 so most players can join without changing much.
The server has a SkyBlock RPG mode where you can grind and progress over time. It also has a WorldSMP mode that uses Lifesteal so the fights feel more intense when you lose or win hearts.
If you like PvP there are modern PvP minigames like FFA where you can just jump in and fight. There are also classic 1.7 and 1.8 style PvP modes like Practice and Rush or MLGRush so older PvP players can feel at home.
Overall the server seems made for people who like to chill but still want real PvP and some grinding. It is focused on a mix of SkyBlock RPG Lifesteal and different PvP games so you can swap modes when you get bored.

