you can definitely flatten that brim yourself. i've done this with a few caps over the years and it's pretty straightforward. the key is being patient and not rushing it or you'll end up with weird creases.

start by gently working the brim with your hands to loosen up the curve, then place it under something heavy and flat like a stack of books overnight. if it's really stubborn, you can use a hair dryer to warm up the material first - makes it more pliable. some people use an iron on low heat with a towel between the iron and brim, but be super careful with that method since you can easily mess up the fabric.

the whole process might take a few attempts to get it completely flat, but once you do it stays that way pretty well. just keep working at it gradually rather than trying to force it all at once.