Hi @RokeJulianLockhart, just some additional thoughts to consider...
Kubuntu is an official "flavor" of Ubuntu. That is, its supported by Ubunutu, and has the same LTS and non-LTS releases Ubuntu has.
KDE Neon is based-on an LTS Ubuntu, but is not supported by Ubuntu. It contains more recent KDE components, and is maintained (not sure about supported) by KDE devs. So there's definitely pro's and con's to both. But I'm sure both are good either way.
I ask about Kubuntu explicitly because it's Qt-based, being the KDE Plasma variant, so I prefer it for verifying Qt bugs.
While KDE is Qt-based, it actually uses Qt-derived libs, rather than Qt per se. So while it really doesn't matter, if you really like to use Qt on Ubuntu (as I do), then I can recommend Lubuntu, which is also an official Ubuntu flavour (supported by Ubuntu), but using the LXQt desktop by default instead. LXQt is a lightweight Qt-based desktop environment, so much more Qt-pure than KDE is (though again, it really doesn't matter). It's certainly not as feature rich as KDE, but then its without KDE's bloat too. LXQt suits my needs perfectly (by largely staying out of my way), but of course might not be right for you. Worth knowing about anyway.
Cheers.