Install Debian as a server with no GUI, install docker on it and start playing around.

You can use Komodo or Portainer if you want a webUI to manage containers easily.

If you put any important data on it, set up backups first, follow the 3-2-1 rule by having at least 2 backups in place.

The problem with stuff like yunohost is when it breaks you have no idea how to fix it, because it hides everything in the background.