Fedora silverblue
The main system OS is immutable and tracked by a git like system, which means to upgrade, or downgrade your whole OS to a release you just pull in the 'tag' you want, and it just does it.
Can also side grade easily to respins of the OS using this too, just add the remote and pull in the image.
Florp, to me, is not a serious project and best avoided unless you like playing with random hobby toys. Not sure why people are so up in arms over what some random tiny hobby thing does