1) A playlist of multiple different video files in VLC as a source for ...
2) OBS Studio, which produces RTMP to be consumed by ...
3) nginx, which calls ffmpeg to produce multiple birates and resolutions to be rebundled as HLS to be sent to ...
4) a "live TV" channel of my own specification as an input to JellyFin, which can be read by ...
5) various clients on Roku, Apple TV, Firestick, Chromecast "apps"
At this point, I don't think the industry will ever really settle down to something manageable.