My experience was also that Plex is better at working around the limitations of Apple TV, compared to Jellyfin. E.g., the native, built-in Apple TV video playe

My experience was also that Plex is better at working around the limitations of Apple TV, compared to Jellyfin. 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.