Tuxedo OS, as preinstalled on my Tuxedo machine. It is just a heavily tweaked Ubuntu flavor with Plasma as a default desktop and sane defaults (firefox not as a snap, but as a .deb file). Everything worked so well out of the box that I did not see the point in installing Arch. I also love the fact that Plasma is kept very much up to date. In comparison, Kubuntu 24.04 still has Plasma 5., whereas I currently run 6.1.4.