What are you talking about. Please clarify if this is actually true:
I don’t plan to access it anywhere but home.
This would mean that you only want to access Jellyfin when you, and the device you are watching your show/movie on, are at home, where the Pi/server also is.
Is this correct?
If so, then questions about VPN, Certificates, DNS,.... do not matter.
- host Jellyfin on the Pi, e.g. with IP 192.168.10.20 on your local network
- open the Jellyfin app on your TV/Phone/PC, connect to http://192.168.10.20:8096/
- done
Now you can access it at home, and only at home. I honestly fail to see where a VPN would even come into the equation here (again, if you wish to ONLY watch when you are at home, as you've said).
Then honestly, you have other problems than setting up Jellyfin.
For real though, if you think someone is (or might be) listening in on your local network, i.e. have physical access or compromised one of your machines, then the Jellyfin traffic is the least of your problems. Pick your battles. What's the worst that could happen here - someone gets to know your favorite show?
Ah, I see. On your PC you should just be able to set a static route over the physical interface for 192.168.0.0/24 (or whatever your local network is) which takes precedence over the VPN. For android.... Oof, no idea. Probably need root.