I've also been using silverblue for about a year, it works well. Didn't know about IBM acquiring Rad Hat, sad news.

For a similar experience there is Vanilla OS that I tried briefly and that seams to have similar immutability features and hastle free setup with a vanilla gnome desktop. It's based on Ubuntu.

There is also NixOS which takes the immutability to another level. The entire system with all packages are configured in a config file. Which is nice if you want to have an identical setup on multiple machines but makes it a bit less user friendly imo.