I’ve had no trouble setting up jellyfin on Roku, Google/Android, and FireTV. It seems AppleTV is the only major one lacking support right now, and that will hopefully be addressed soon.

I tried out Plex (and Emby) before Jellyfin and was annoyed how much functionality was locked behind a paywall even though I was hosting the content myself. Jellyfin is completely free and lets me add as many users on as many devices as I damn well please.