If anybody’s interested in running Firezone with nginx, we are doing this for the free Jitsi offering at meet.jit.si. We publish our infrastructure as an open source example of how to deploy Jitsi at scale. Our Firezone configs are set up by this ansible role: infra-configuration/ansible/roles/firezone at main · jitsi/infra-configuration · GitHub
Probably most interesting for a Firezone admin are the /files and /templates subdirectories, which contain a custom docker-compose and nginx configuraiton. If you aren’t using ansible, just fill the templates in with whatever you need for your own environment.
I’d love to see an official Docker distro of Firezone that makes it easier to use custom SSL certificates. There doesn’t seem to be a clean way to do it with Caddy which is why I ended up going down this path in the first place.