I recently bought the new 2022, Ethernet wired, Apple TV.
Now Plexamp and the Plex app on my IOS devices can’t stream to my Apple TV Plex server any more. IOW, I can’t use Plexamp and my Plex app on IOS as remotes for my Apple TV Plex server.
The only connections I am being offered are both my Chromecast devices.
Servers don’t run on an Apple TV, Do you just mean the Plex player app? Is whatever computer your Plex Media Server installed, on the same network? if you choose Airplay and Bluetooth Devices does it show up there?