I am forced to use Ubuntu 24.04 on my work laptop because that's the only Linux my company supports (and I refused to use a MacBook). Desktop experience is quite horrible and buggy compared to Fedora with up-to-date KDE Plasma on my own laptop. Quite unfortunate that both of the big players - Red Hat and Ubuntu default to GNOME. What is giving hope though that Valve made the correct choice for the Steam deck desktop mode.
What prevents you from doing apt imstall kubuntu-desktop ? No root access ?