Ubuntu Core, based on Snaps, is very much not ready for prime time IMO. It’s kind of a mess outside of server use.
Look instead at Fedora Silverblue, Vanilla OS, and for the bleeding edge of immutable systems, GNOME OS.
KDE is about to launch their analogue to GNOME OS relatively shortly, named “Project Banana”. These two are not exactly distros as they do not distribute the kernel, they are simply platforms that layer a bunch of images together to create a stable, reproducible system. There’s also OpenSuSE Aeon, but I don’t like its style of immutability as it’s immutable by rootfs lock-out rather than immutable by image.
As for advice, learn how to use Distrobox / Toolbx containers. If you’re a developer, this is where you will be working.
Immutable Linux is still young, and a lot of software isn’t written with it in mind, so expect some growing pains.
Where my bitchat