Does Steam define server regions or do developers have control over them?

Hey, so I was wondering if Steam defines the server regions in a way like for example western Europeans can’t connect to eastern European servers. Or can the developers make the servers appear to for example everyone globally when using Steam servers if you just have your own app ID? I’m hoping someone could shed some light on how the Steam servers work. I’m a bit unfamiliar with this.

Developers have control over regions, server provider, hardware/software, server specs (cpu cores, ram, hdd etc).

Ok that’s great. Are they editable in Steamworks or somewhere else?

Steamworks doesn’t provide servers.

Oh, do you know where the regions can be edited? I looked up and found out that you can use something called ELobbyDistanceFilter, although I couldn’t find anything in the Blueprints