But here is the thing: It is a wired Ethernet network between the server for both and the Apple TV, so there is absolutely no justification.
Jellyfin is going to be THE answer one day, but still has some growing to do.
E.g., the native, built-in Apple TV video player expects everything in an MP4 container, and Plex appears to seamlessly repackage content into MP4, whereas you need to dig into the settings to force an MP4 container and force the native player on Jellyfin. Otherwise, Jellyfin will try to use VLCKit or some other player that has other issues (like with HDR content).
Apple TV also has very limited subtitle support in the native player, and Plex does better at accommodating that.
I'm assuming Jellyfin is closer to parity on hardware with more capable native players, though.
When that happens, I open up Handbrake and re-encode the media as H264 (8-bit), which Jellyfin can direct-stream to all clients. https://jellyfin.org/docs/general/clients/codec-support/
0 issues, InFuse is much better at doing the playback correctly.
Of course transcoding on the fly and stuff is there but I just want to stream the direct file to the tv so none of that matters.
*edit: For anyone else reading down here the parent's solution was better for me vs Plex. Simply streaming through infuse via SMB removes all the issues I don't want to deal with with Plex as it has gotten worse over the years and has invaded my purely local setup more and more. As long as it is encoded in a way Infuse can read it works great. I didn't have a file Infuse couldn't play.
Plex has a much better UI and UX than anything else.
Jellyfin split off from Emby years ago, which does have a commercial side. Perhaps their Apple TV client is better?
/done