Once you have Cloudflare (or one of many other options) set up it works as easily as you describe. And no port 80 open or special snowflake reverse proxy rules.
I'm aware of it and I'm using it. But I feel uneasy when some software can wreak havoc in my DNS, even if theoretically. For example Cloudflare does not have some kind of very limited "letsencrypt tokens".
I'm replacing acme.sh with Lego currently. https://go-acme.github.io/lego/
Once you have Cloudflare (or one of many other options) set up it works as easily as you describe. And no port 80 open or special snowflake reverse proxy rules.