I don’t think regular Arch is the best for new Linux users at all but their are a few Arch based distros with graphical installers.
I’d you are trfh savvy, the Arch install process should be ok though.
Of the 2 you suggested, u would go with Kubuntu. KDE is a very popular desktop environment and Ubuntu is solid. I’ve moved distros quite a bit but always go back to Ubuntu-based. I’ve been on Mint for the last 6 or so years.







What’s keeping me from switching is that I switched about 12 years ago.
I can’t vouch for this particular software but from my experience with using Mint full time for the last 6 or so years is that regarding troubleshooting software, if a fix works on Ubuntu, it will more than likely work on Mint.