

Conciseness and directness help.
As an example, there was someone I worked with that tended to ask around a question.
“What do you know about x? What do you know about y? What do you know about z?”
Instead of “How do I get from x to z?”
I think they just want to understand the underlying process. And I can understand that. But I wasn’t their mentor and it was at times frustrating.
Not suggesting OP is doing this. Just a general thought I had in regards to the question.
Maybe self host your own VPN on a VPS and connect the jellyfin server as a client as well as any other devices you want to see that jellyfin server as other clients and configure the VPN server to not override your default routing and to allow clients to see each other? In my head I don’t think that would conflict with your protonVPN connection.
Your traffic would be encrypted between devices so I wouldn’t say https is nessesary and thus no certs needed.
The rubs that occur to me are that I’m not sure you can do this on a free tier VPS which is the only option I see given your financial limitations. And your devices all need to be able to connect to said VPN.
Edit: Slightly less worse English.