I can’t speak for all Jellyfin clients since I only use Android TV and Windows clients but on those two platforms you can tell Jellyfin to continuously play or to stop/prompt at the end of each episode.

Tdarr will do this but if your server is struggling with unmanic then no solution will work well for you. I think possibly you might be doing more than just remuxing to remove audio and subs if it’s thrashing your server.

Not in any easily-readable format, no. You can look at PR’s and the like but that’s a bit of a pain. I imagine they’ll release something once they feature freeze in a week or so.

Fantastic work. Really looking forward to 10.9.