Caddyfile Wordpress Multisite

The idea was to automatically generate user sub-websites, like i.e. demo-pages for wp-plugins.
For that functionality to work multisite is necessary.

I am pretty new to the whole web-development topic, so of course I am thankful for any tips about how to accomplish just a solution without using multisite (the inter-dependability is indeed an issue)

It is a clean wp-installation just using caddy no nginx or apache