"CMS-free" as in "does not depend on additional software to manage content". Postgres and S3 through MinIO are my preferred choices, but you can change that to anything you'd like to use instead.
Glad you like the in-place editing. I'm also for the first time happy with the experience. You can press CMD+E for editing and CMD+S saving, and there's no layout shift, so it's really convenient for quick edits. :)