Finding a good client is hard. Folks recommend the Nvidia Shield Pro. Finding something that plays all the formats and can pass audio through hdmi to a AV receiver. Umcompressed HD audio, HDR/10/DolbyVision. Etc.

If I can just pop a debian machine down, that is great, but a hardware guide would be nice to see.

Where?

Looks like there is an LDAP auth plugin: https://github.com/jellyfin/jellyfin-plugin-ldapauth

If you ran such a beast.

Jellyfin has a (plugin) opds server for ebooks that use the same accounts as the rest of jellyfin. I use calibre to deal with organization/metadata.

If you have a bunch of plex users, switching to jellyfin might be a bridge too far.

I wrote this: https://github.com/josefwells/nft_tool

Almost exactly your same situation, I got mad and took control of my firewall.

This should be in the lemmy code. Federate out accounts.