Edit2: OK Per feedback I am going to have a dedicated external NAS and a separate homeserver. The NAS will probably run TrueNAS. The homeserver will use an immutable os like fedora silverblue. I am doing a dedicated NAS because it can be good at doing one thing - serving files and making backups. Then my homeserver can be good at doing whatever I want it to do without accidentally torching my data.
I haven’t found any good information on which distro to use for the NAS I am building. Sure, there are a few out there. But as far as I can tell, none are immutable and that seems to be the new thing for long term durability.
Edit: One requirement is it will run a media server with hardware transcoding. I’m not quite sure if I can containerize jellyfin and still easily hardware transcode without a more expensive processor that supports hyper-v.
Immutable systems are useful for separating the system and application layers and to enable clean and easy rollbacks. On servers the applications are often already separated anyway through the use of container technologies. So having atomic system updates could enable faster and less risky security patching without changing anything about how applications are handled.