Can anyone explain why Wayland exists or who cares about it? X has been around forever, it sucks but it works and everything supports it. Alternatives like NeWS came around that were radically better, but were too soon or relied too much on corporate support, so they faded. The GNU project originally intended to write its own thing, but settled for using X. Now there’s Wayland though, which seems like a slight improvement over X, but mostly kind of a lateral move.
If you’re going to replace X, why not do something a lot better? If not actual NeWS, then something that incorporates some of its ideas. I think Squeak was like that but I don’t know much about it.
Can you verify with wireshark that the traffic is only going through your lan? I’m not hip enough for nginx but I used to have to run apache under gdb all the time to trace random errors from the server. That would be next, if the traffic is really local.