Noted with thanks.
Ryan does warn that Flakes are experimental and users always run the risk of wrecking their system but Ryan doesn’t make it quite as clear as you have. The fact that Flakes does not support roll backs is pretty significant.
Having said that, I decided to back out of my current effort to learn how to use Flakes. I was originally going to experiment with just Hyprland and it’s ecosystem with Flakes and keep the rest of the system on the stable or unstable channel. I will shelve these plans for now and return to Ryan’s guide at some point in the future when I have learned more about nix.
Thank you @dtannock.