This server is called RefinedVanilla and it is a true vanilla anarchy world. There are basically no rules except you cannot use hacked clients. You can build bases destroy stuff explore far away and try weird experiments. It tries to stay exactly how Mojang made Minecraft so it feels like singleplayer but with other people.
The owner uses Fabric so the game keeps real vanilla mechanics. Redstone works like it should. TNT chains and piston machines act like singleplayer. Tick timings stay the same so technical players can make farms and machines without everything breaking.
The performance is tuned a lot. The server changes simulation distance mobcaps and render distance while people are online. This keeps it running smooth even when more players join.
There are a few gameplay notes. The nether roof is allowed so you can travel super fast. Chunk trailing is patched. Portal chunkloaders will work but they stop when no player is close in either dimension.
If you want a server that feels like real vanilla Minecraft with almost total freedom this one is pretty close.
