If you are on version 24H2 and later, the Email account should be displayed on the Bitlocker key screen in a partial format. Did you check it by any chance?
Also, at a point in time, there must be another account, which can be either MSA or your work account or your school account, configured, which might have the key.
You would need to ask the school administrator since the Bitlocker key is in their Active Directory.
I’m eager to hear back and work together to find a solution.