1) Install Ansible
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
That reads like "draw a circle; draw the rest of the owl".
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.
1) Run curl command to install Dokku
2) Set up domain to point to my server
3) Run 3 Dokku commands (https://www.hackerneue.com/item?id=41358578)
4) Add remote git url to my repository
5) Git push to that remote
6) Done