Like others mentioned file structure is the most important. In addition you can also grab the AniDB plugin and set it as the primary metadata source in Jellyfin. (I had it for quite a while so dunno how much difference it makes compared to TVDB, but from experience I practically never had wrong metadata on an anime)

I have been using Authentik for several years now, works great with k8s. Not sure about the difference between Keycloak and Authentik tho (feature vise)

I use Longhorn for generic PVC and static NFS shares for large files. Longhorn creates scheduled backups to a NFS share, which is then backed up to a Backblaze bucket. I have yet to test restore from Backblaze tho :D

Of course this means that I have 3 copies of the same data across multiple Nodes because of how Longhorn works. That’s why I usually don’t create large volumes, just enough to get the app working