I'm currently maintaining a laptop with kubuntu (for someone else), and I honestly cannot recommend it.
They have kind of messed up the updates in their Plasma flavor, Discover routinely just fails to do the updates with a completely meaningless error message. I suspect the underlying issue is lock contention with the background service "unattended-upgrades.service", but I'm not sure, because, again, that error message is ridiculously unhelpful. Also, said unattended-upgrades service does not seem to actually be doing any upgrades.
On the last install, also, the attempt to upgrade from Ubuntu 24 to 26.04 LTS, the upgrade failed in a spectacularly fashion that left the system mostly bricked in ways that could only be solved by a fresh reinstall. During the process, a few error messages made it look like the problem was hardware faults on the SSD, except when I then tested the SSD from a rescue disk using dd, smartctl, and iotester from https://github.com/guidow/iotester, I could find absolutely no indication of any faults on that drive whatsoever…
Granted my opinion on kubuntu may be a bit colored, because right this moment, I'm quite frustrated with it.
Also, installing massively important software like Firefox or Thunderbird through snaps instead of packaging them properly is just asinine.