CachyOS is Arch. It’s close enough that any searching about how to modify it will be applicable. You can even install Arch and apply the same modifications that CachyOS has. My personal experience is that it just works. I moved from Bazzite, an immutable distro wasn’t for me.

Their unifi controller container is definitely one of the more popular ones.

For me, it’s still better than Jellyfin. I can’t wait until I can switch over. I have both Plex and Jellyfin containers going simultaneously and Plex just works better and is a more reliable experience.