Here is the video I followed for SWAG. Note that this (and most of IBRACORP’s guides, which are all fantastic) uses Unraid as the OS, which automates a lot of the processes.
And here is a written guide by the same group to go with or replace the video if this is more your speed: https://docs.ibracorp.io/swag-2/
I’ll be honest, even for “beginners” (which I was when I started this) this is still a lot to take in. Let me know if you run into any specific questions and I can try to help you.
It can pass through. There is even an official Authentik guide on the various methods specifically for Jellyfin: https://integrations.goauthentik.io/integrations/services/jellyfin/
Same with Authelia, though I don’t have a link for that on hand.