I have everything in its own VM, and Proxmox has a pretty awesome built in backup feature. Three different backups (one night is to my NAS, next night to an on-site external, next night to an external that's swapped out with one at work - weekly). I don't backup the Proxmox host because reinstalling it should it die completely is not a big deal. The VM's are the important part.

I have a mini PC I use to spot check VM backups once a month (full restore on its own network, check its working, delete the VM after).

My Plex NAS only backs up the movies I really care about (everything else I can "re-rip from my DVD collection").