Solus
The great debate
I would go with Manjaro, for the following reasons:
1. The rolling release nature of it, as well as the presence of the AUR, makes obtaining software and keeping it up to date extraordinarily easy. This is especially good for new users, who are already going to find the method of obtaining software on Linux different from what they're used to. On, say, Mint, you end up with a patchwork of PPAs and external repos and .debs and snaps/flatpacks/appimages and other shit to get all of the software you want. People will bitch about the stability of rolling release distros (which I never really have any trouble with), but inevitably, when you do a major upgrade to a new version of Mint, everything is going to fucking break.
2. Mint dropped their KDE version, whereas Manjaro has a very up-to-date, rather polished KDE variant. Cinnamon isn't bad, but I'm not sure why you'd use it over KDE these days, which is significantly more featureful, less resource intensive, Qt-based, proper filepicker, etc.
yikes
there's another one?
wtf is manjaro?
why is there a new one every day?
*stable
they're both shit