I can think of/have already read:

the series that shall not be named, The Magicians, the Scholomance series, and Witch Week from the Chrestomanci quartet

Magic for Liars (from the perspective of a non-wizardly PI whose sister is on the magic school faculty and who's investigating a murder on campus)

- oh and have read some of the Discworld Wizards Books

Wizard of Earthsea has magic school stuff

true, the first Earthsea book is all magic school + Dealing With Fucking Up Bad At Magic School (i love ged and his bad life choices)

Pratchett's Tiffany Aching series is all about witch school

What age range?

Or is that a 'doesn't matter even if it's more for tweens'

honestly looking more for tweens/teens/young students (and possibly presumed readers) but open to the university-ish ones as well

- for I had also read Wizard of Earthsea and Year of the Griffin

*forgot

I had not got to Tiffany aching!!! I ignored all advice and was reading disc in chronological order and fell off about halfway through

and then the Mark Reads videos all went down

it's.. been a long time but I think Wizard's Hall was a magic school series.

(Tiffany Aching is more YA than the standard Discworld books, I'd say!)

the bartimaeus trilogy? not really a magic school but the first book has like. magic learning for a little boy

no, I'm specifically looking for school-setting stuff

lmao.... carry on by rainbow rowell

it's an obvious pastiche of harry potter but there is a magic school

I think The Black Magician trilogy by Trudi Canavan had a book involving magic school. (Although I read it 20 years ago so I can't remember much.)

lmao how could I forget carry on

I guess I SHOULD read it if Im doing a proper subgenre review

...does it have to be a good magic school?

no

The Wizard Heir by Cinda Williams Chima involves a Very Bad wizard school.

it is a distinctly anti-wizard series where Wizards are a ruling class among magical guilds and they use that to be Assholes

your mains are dissenters to that situation

it's the second in a series, but each one involves a single protagonist and they let you start anywhere really.

cool

Vita Nostra, but it’s mot YA

A Dark and Drowning Tide is mostly away from the school, but that is the back drop

Katabasis

witchlings!

To Shape a Dragon’s Breath is more dragon school than magic school

Babel

The Atlas Six series

I’m scrolling through my read books on storygraph lol

The Alamaxa Duology, but only in fits and starts

Rivers of London probably doesn't count because it's more 'wizard protege/mentor, wizard school is not really a thing any more' but whatever I'll recommend it whenever it's even vaguely relevant

Tiffany Aching may be YA but it's excellent

and lol, I was going to remind you of Year of the Griffin (which was cute)

The Worst Witch might be a little too kid lit, but I remember it being fun.

Not sure if the Young Wizards series by Diane Duane would help you, as it's not a school setting per se, but it's kids learning how to magic sort, similar to the Rivers of London books.

Young Wizards is solidly YA (most of it written before that was a marketing category) and also seconding Tiffany Aching a little Different from most Discworld and excellent.