What you’re describing is common when painting on top of silver or chrome paint. In order for subsequent layers to stick and not peel off, you need to do a little prep work. When I spray silver I let it dry completely for a day or more, then wipe it down with a damp soft rag to remove any surface residue. Then I airbrush Humbrol Satin Cote to “seal” the silver, and when that’s dry I polish the surface with #000 steel wool. I had to redo the back panels on my helmet after some problems with paint peeling and I’ve found this process helps. I also airbrush in several thin layers to ensure the paint is adhering and curing.
If you’re determined to paint it yourself, you can do it. It just takes some trial and error or you need to take the time to test your process so you don’t lose hours of work. You can do it!