Poorly, Kubuntu uses the broken Plasma 5.27 for a while until the next release afaik.

Really that was kind of the plasma guys fault, but Plasma 6.0.2 or so was really stable. Perfect LTS candidate. Then the new features came in, now it is stable again (on Fedora).

I used Kubuntu and the outdated Plasma and many packages were annoying. Nowadays snaps, and removed base packages.