There is multiple ways you can paint a metallic look on foam. Here are some paints you can use to achieve that mantellic look.

First thing to do before painting is priming your foam so the paint will stick to the Eva Foam.

Two Recommend choices are Flex Bond or Plasti Dip.

Lets start with the old fashion way first with some Primacryl paint and a paint brush.

PRIMAcryl Look

Quick and Easy look but your brush strokes will be noticeable up close.

https://www.schmincke.de/en/products/acrylic-colours/primacryl.html

A second choice is to use Rub’nBuff all you need is some Rub’nBuff Paint and a piece of cloth to rub it on.

Rub’nBuff Look

Add a shine to your foam but will smear easily and isn’t a smooth look.
https://www.amaco.com/t/mixed-media/metallic-finishes/rub-n-buff

A Third choice is a chrome spray paint for a fast an easy apply.

Spray Paint Look

Has a smooth finish but isn’t a bendable material causing it to crack like so.

https://www.belton.de/en/products/belton-special/liquid-chrome-effect-paint/

Spray Paint Look After Bend

A forth choice is to air brush it on with Vallejo paint.

Air Brush Look

Airbrush adds a smooth texture with some shine and can also be bendable unlike the spray paint.

https://acrylicosvallejo.com/en/category/hobby/model-air-en/

But for the best option and most expensive is Alcald II ALC107 Chrome paint it has the best shine and has the smoothest finish.

Air Brush Look with Alcald II ALC107

For the Full video.
https://www.youtube.com/watch?v=OXUnVaSAY6c&t=239s

Other painting tip I would recommend these video’s

Another Way to paint a metallic look

Painting Details in Eva Foam

How to paint a metallic looks quick and easy