edit: Fedora it is then!

He will be running the AMD 9800 X3D w/ RX 9070 XT, B850 motherboard.

I am deciding between either Fedora (probably KDE) and Bazzite (also KDE), but I'm not sure whether an atomic distro would be better/worse for a newbie.

As far as I understand, atomic distros can be easily rolled back after an update, but you are unable to use apt/dnf/etx, you need to use Flatpak, I think. Would that be limiting for the average user? Also, does Bazzite have better driver support for newer AMD hardware compared to Fedora?