2) Create a playbook which pulls from your GIT, sets the DNS and installs Caddy (or apache+certbot or whatever) (~5min)
3) Run Ansible
You now don't need docker, can change to any other cheaper hoster any time you want and you don't have the limitations of "serverless" services
Look, I used Ansible for years. And chef. And puppet, so I've been around that particular block a bunch of times. There's no way you legitimately think that someone can, with no previous experience, create a playbook that does all you need in "~5min".
I ansible a good tool? Absolutely. Does it do what a tool like Dokku (or some of the others mentioned) do? Absolutely not. They aren't meant to compete, either.