How to "fix" rusted metal fire door?

Question

Attached are photos of the door in my basement leading to stairs to my attached garage. I bought the 2006-built house in March 2022 and this existed prior to our arrival. The previous owners "deferred" a lot of maintenance and upkeep. We are unsure of the source of such an obscene amount of moisture as to cause this level of rust (there is no indication elsewhere in the basement of any sort of flooding, so it is assumed to be from 16 years of a "damp" basement). For the sake of this question, let's assume the moisture problem is solved by a heavy-duty dehumidifier. How would I best fix this metal fire door? They cost approximately $850 to replace, so that's out the window. It is very drafty in its current state. I was thinking of removing all rust with a wire brush wheel, followed by two coats of rustoleum, then perhaps riveting sheet metal to attempt to return its original shape. What do you all think is the best move here? Additional photos:

Answer 1

Whatever you do to that door is a temporary "band-aide" The rust will come back. There isn't enough metal skin left to grind off the rust so it won't reoccur. You can sand and grind as much off a possible, then apply a rust convertor and paint. Then save for a new door as you will need one.Rust convertor

Answer 2

That door can not be saved with paint.

Unless you want to tac weld sheets of metal to it, forget about it.