For the record those "sharia mortgages" basically sound like "charging interest but calling it something else". But even that's not really possible with a student loan.
And they're almost certainly more expensive, which sort of seems to go against the whole idea?
No, you don't get it.
Interest is specifically bad because reasons. Charging extortionary rent is fine. /s
But I do wonder what interest rate these Sharia Mortgages are equivalent to. It's hard because from my brief search, I can only find UK ones: this doesn't seem to be as common in the U.S.