Have you tried creating a subdomain for the camera and then proxy that to your camera? Ie, camera.example.com [CNAME -> example.com] -> nginx -> 192.168.x.x? Then embed the camera.subdomain.com in your WordPress however embedding videos is done?
I installed immich snap in a vm and i haven’t had to mess with it since.
Literally just finished configuring headscale on a free (pay as you go) oracle vps because I’m behind cgnat. Getting tailscale on pfsense to connect to a headscale server was a chore but finally got it.
You didn’t explicitly ask for other suggestions but here’s mine anyway; I’m running tailscale on my pfsense router and sharing my home network cidr over tailscale like someone else suggested. So all my dockers and vms are available over tailscale from anywhere. It’s been highly convenient as my home internet connection is behind CGNAT.
I mean, i don’t know for sure either. But it seems like it would work.