Mother of Learning by Nobody103 - free webnovel, complete now I think. Wizard student gets stuck in a time loop and uses this opportunity to become OP and solve the mystery.

Diane Duane's Young Wizards series, if middle grade is okay.

I second Earthsea.

Spellwright seems like it might be good but I haven't got far in it yet.

The Black Magician trilogy by Trudi Canavan. It's been a long time since I read this, but Canavan is one of those authors who's popular and has a lot of books out but is weirdly never mentioned online.

Also try L.E. Modesitt Jr. If you haven't. Either the order mage series, or Imager maybe. Most anything by him will have a lot of studying. They're very good if you like his specific flavor of writing.

Edit: Vita Nostra being described as just "magic school" is very funny to me, although I do see where it comes from lol.

Edit 2: I remember the Charlie Bone books being good, but again those are middle grade and it's been ages since I read them. No idea if they hold up.