Totally get The Foreman. Worst piece of garbage I’ve ever used.
I do use ansible to set up my own repository management/lifecycle environment servers nowadays, specifically to get rid of Foreman.
Why do you dislike ansible? Got to say that I love it, especially compared to stuff like Puppet and SaltStack.
OpenSUSE MicroOS or Fedora CoreOS. If you’ll be using containers you’ll have a great time. If you don’t want to deal with transactional systems, then there is literally nothing I’d rather use than Debian.