I have some videos I might be interested in sharing on a Jellyfin server, as well as interest in viewing videos on someone else's shared server. I have a question: What options do you have for hardening security-wise? I have the server hosted on a local machine and don't wanna get pwned if I can help it.
Actually, looking in that guide you linked, the change to add https is a very small change in the config file as well. Perhaps you mean doing port forwarding in the router or setting up a domain/DNS is difficult? But those parts have nothing to do with Caddy itself.
Try looking at an equivalent guide for its competitors Nginx or Traefik. They're far more complex to get set up.
If you use any other domain name, Caddy will attempt to get a publicly-trusted certificate; make sure your DNS records point to your machine and that ports 80 and 443 are open to the public and directed toward Caddy.
First OP needs to configure his DNS service.
Then he needs to port forward 443 (if I'm reading the instructions correctly).
I have my Plex server in docker container that automatically restarts with the latest image once a week. I believe most vulnerabilities will come from outdated software.
Then I have nginx reverse proxying in front, I'm sure there's additional safeguards I could throw in there but my instance is private.