Hi. I am a software engineer with a background in IT security. My girlfriend is a literal network security engineer.

I showed her this thread and she said: don't bother, just use http on your local network.

Anyways, I am going to disengage from this thread now. Skepticism against things one doesn't fully understand can be healthy, but this is an insane mix of paranoia and naïveté.

You are not a target; the things you are afraid of will never happen; and if they did, they would not have the consequences you think they would.

Your router will NOT magically expose your traffic to the internet (what would that even mean?? Like, if it spontaneously started port forwarding to your Jellyfin server (how? By just randomly guessing the port and IP???), someone would still need to actively request that traffic, AND know your login credentials, AND CARE).

Your ISP does not give a shit about you owning or streaming copyrighted material over your local network. It has no stake in that.

Graphene is not an ultimate arbiter of IT security, but the reason it "distrusts networks" is because you take your phone with you, constantly moving into actual untrusted networks (i.e. ones you do not own).

Hosting Jellyfin on Graphene will not make it more secure, whatsoever.

If every device is assumed compromised, and compromising devices with knowledge that you watch media is a threat in your model, then even putting an SD card with media in your phone and clicking play is dangerous. Which is stupid.

If you actually assume your router is malicious, then please assume that when you initially downloaded your VPN client, it was also compromised and your VPN is not trustworthy.

The way I see it, you have two options:

1. educate yourself on network security to the point of being able to trust your network setup; or
2. forget about hosting anything