I do wish more effort was made to polish all the bits and pieces because all of this exists in some form. I suppose some of it is that everyone is doing their own slightly different thing; NixOS lets you boot to earlier generations, but only by completely turning the filesystem inside out, OpenSUSE can do snapshots, but using BTRFS which means that not many other distros even can use the same implementation, ZFS is the bee's knees but on Linux licensing always adds friction, Ubuntu made boot super smooth via Plymouth but it's very... Ubuntu.
Anyways. If you're in a position to run Linux on ZFS, may I suggest zfsbootmenu?
> ZFSBootMenu leverages the features of modern OpenZFS to allow users to choose among multiple "boot environments" (which may represent different versions of a Linux distribution, earlier snapshots of a common root, or entirely different distributions), manipulate snapshots in a pre-boot environment and, for the adventurous user, even bootstrap a system installation via zfs recv.