Tbh, Ubuntu/Kubuntu is fine if you're not a Linux die hard and just need a balanced OS that either feels more like macOS (in that case go for vanilla Ubuntu) or like Windows (in that case go for Kubuntu).
Ubuntu is even more problematic for non-Linux die hards because they won't know (or want to) deal with all the issues with snap (like slow app startups and other compatibility issues), or the inevitable package conflicts or other issues when it's time to do a dist-upgrade. See: https://news.ycombinator.com/item?id=42949222
My mum was on an Ubuntu base as well (Mint first, later Xubuntu) but after both eventually experienced failed dist-upgrades (no GUI after reboot), I switched her to an immutable distro (Aurora) and it's been rock solid so far. And in the event something does break, rollback is as simple as selecting the previous image from the boot menu.
So for normies who want a macOS like experience, I'd recommend Bluefin, and for Windows-like, I'd recommend Aurora. And Bazzite for gamers. All of these are Fedora-based immutable distros and have none of the stability issues that Ubuntu-based distros have, plus the generally newer kernel+mesa stack compared to Ubuntu means you'll also have better compatibility with newer hardware.
