Both are more on the tinkerer-side, and for university you need something reliable and easy to use in my eyes.
And that might be Fedora Silverblue/ Atomic (or universal-blue.org to be more precise for QOL-tweaks).
It is definitely more simple, stable (release cycle) and also more reliable, since there’s only one base (Fedora packages + your DE), and therefore less configuration variability.
I’d also lose access to the AUR
No, you wouldn’t. Neither on Nix, nor on Fedora Atomic. Especially on Silverblue you layer and containerise a lot, and you can always use the pre-installed and self updating Distrobox to install Arch and use the AUR. That’s also what I do, and it works fine, even though I almost never feel the urge to use it.