I had a similar experience after switching to Fedora Silverblue (but any of the immutable Linuxes will probably do - and over time, I'm sure most will be like that). Had set aside a bunch of time to do a major version update, everything fully backed up, and then it was done in a couple of minutes. Literally no different from any other update.

I've done more than a handful of major version updates since then, and almost don't bother to backup any more.