I'm fully Dockerized (well, uhh... Podmanized) and I'm dual-wielding Plex and Jellyfin. Runs smoothly and both only have read to the content. All management of the media is handled by the *arr stack anyway. I even set up a volume for Plex to throw conversions into that Jellyfin can't see. I'm currently personally using Jellyfin and I'm waiting for Jellyfin to be good enough (or Plex bad enough...) for the users I share with to switch over.
I can definitely recommend that setup.
And here I am wasting my money on 24 TB obsolete HDDs when I could have just bought SSDs.