That's for Caddy 1.1

In Caddy 2 and higher it handles the cert stuff automatically with Let'sEncrypt.

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.