I was connected to the uni’s wifi, which I access with my institutional account, on my personal laptop. If using the app Notion - accessed with my personal gmail account - and writing on it, what can they see? do they have access to what I’m writing? Do they just see I’m using it?
No more than someone running a coffee shop wifi would see. Some basic traffic for name resolution then encrypted traffic for web browsing that they can’t read. Unless your notes application transmits in cleartext (unlikely).