I found Iperios and it is a modded server where you can make your own nation. You can pick your own kind of government and make laws and ranks too.

If you do not want to start a nation you can join one that already exists. It feels like a mix of survival with people trying to run their own little countries.

It uses the All the Mods 10 modpack and it says version 6.1. You have to get whitelisted through their discord first.

When you get in a staff member will guide you and give you a beginner kit so you can start playing.