It’s kinda the same issue that some games have, like MMOs. People tend to make new accounts on the biggest and overloaded servers because there is the most activity even though stability could be an issue, or login queues.
It's funny you mention MMOs, because FFXIV has a system that i'm now realizing feels like federated websites.
You have your home world(server) where your character was created and is stored server side, but you can matchmake within your data center as well as visit other servers in your data center.
And then you can also temporarily transfer to different data centers (though the implementation is clunky and has a few restrictions)
a