it seems easier to manage stuff not in docker

Read into Traefik’s dynamic configuration. Adding something outside of Docker is as easy as adding a new config file in the dynamic configuration folder. E.g. jellyfin.yml:

http:

  routers:

    jellyfin:
      rule: Host(`jellyfin.example.org`)
      entrypoints: websecure
      tls:
        certResolver: le
      service: jellyfin

  services:

    jellyfin:
      loadbalancer:
        servers:
          - url: "http://192.168.1.5:8096/"

The moment you save that file it will be active and working in Traefik.