I don't know enough to say which immutable debian spin would be best. For immutable in general, Fedora is probably the most refined. Their GNOME spin is the mo

I don't know enough to say which immutable debian spin would be best. For immutable in general, Fedora is probably the most refined. Their GNOME spin is the most well-known and is called Fedora Silverblue. But they also offer KDE, Sway, and others atop their immutable infrastructure. I think you can get basically all major desktop environments. Here is a non-exhaustive list: https://fedoraproject.org/atomic-desktops/ https://fedoraproject.org/atomic-desktops/ The key here is that you would install almost all your applications via flatpak on the home partition, and the system partition would be very locked down except for the system updater tool. When the system is updated, however, you would be able to tag as many snapshots as you like which would be like git branches for your system. Each could have different kernels, system libraries, etc. If a system upgrade goes bad, you would be able to go back to a previous one. The last two will be saved by default, and you can save as many others as you like. Which would all be efficiently stored and de-duplicated via ostree And your userspace would essentially be preserved as you switch between system snapshots, because it is on its own partition.