Exterior Silver Trim on Windows - Aluminium, Chrome or Plastic and Coated or Not - And how to restore??

Hi All,

2019 Skoda Karoq with metal "Chrome Style" trim.

I popped on some Bilt Hamber Auto Foam on and must have left it too long or the sun must have shone for a bit. It dried out on some of the bright work around the windows. Washed the car and polished it as usual and all well except the metal shiny trim around the doors has "popped bubble" type marks over it on one side of the car. I wanted to get working on it. Can't afford to have the trim replaced so I will have to make do and do the best job I can. I have done some research and it seems the trim could be one of:
 

• Plastic with Chrome and then clear Coated
• Actual Chrome plated metal (v v unlikely)
• Polished Aluminium with some sort of Clear coat
• Polished Aluminium bare
• Something else.

Does anyone know, for this car what this trim is actually make from?

I have already tried:

• A hard rub with some regular polish
• Manual cleaning with t-cut and a teatowel
• A dremmel (on slow-ish) with buffing pad and some lapping paste (W10/1000 grit for about 10 minutes on medium speed along an 18 inch section).

This has improved it a little but not really enough.

Can anyone definitively let me know what the actual material is and what my best course of action might be (other than replacing the trim obviously).

Thanks All.

Paul