Tailscale Funnel will let you expose a host to everyone on the internet. You’ll need the Tailscale client running on either the Jellyfin host or a reverse proxy pointing to it. Tailscale itself will act as a reverse proxy with TLS encryption, plus a DNS server.

Exposing a service to the internet will always present some risk. You should definitely run your LXCs as unprivileged to mitigate the potential damage if an attacker escapes the container, or put the services in full virtual machines.