Originally posted by Opus Krokus:

That may be something we look into. However, if modders can do it, I wonder why the developers can't bother to integrate it.

It's a unity game, it's very much possible for modders to mess with many more things.

For instance Rimworld was not suppose to have multiplayer but people managed to make it work and have it sync between all players, remote controlling a base.

Modders uses these special community made libraries meant for hooking the game's code to it to allow them to make big changes to the game without needing to mess with the source code of the game itself, it's basically code injection of sorts.

Like Harmony.

https://steamcommunity.com/sharedfiles/filedetails/?id=2009463077&searchtext=Harmony

https://harmony.pardeike.net/

Also this for Valheim:
https://valheim.thunderstore.io/package/denikson/BepInExPack_Valheim/

And there is server sided characters which forces people to create a new character for said server, not outside of it.