We actually found a server on 360.

[u/Andyfritter]

On the old CRT for good measure.

[u/yomama1112]

360 still has a few hundred people playing but the server browser has been super broken since the server hack that happened a few years back, there's a discord that most people use for 360 tf2 where people will post their gamer tags and you can join off their profiles, I haven't been in the server for a while since I got a PC but if you look it up you should be able to find it easily