AppleTV supports Jellyfin with the Swiftfin app and the Infuse app.
Jellyfin has built-in configuration support for Homerun HD with their Live TV/TV Tuner module.
It's not as elegant as Plex, but it is FOSS and is avoiding the enshittification that Plex has started. Plex hasn't gone to total shit yet, and is still a private company, but there's been quite a few shifts over the last few years that were not customer focused decisions. If they ever go public I'd give em 2 years before they go to total shit.