Best bet is probably shopping local. There’s a couple retro gaming places near me

If you want to support a US company, buy a Steamdeck and do retro emulation on there. The device components and whatnot are still going to be of mixed international origin.

I've had decent experiences with Lukie Games online over the years. They almost never have good sales though. So it's not a cheap place, but you know exactly what you're getting.

Otherwise I get picky on eBay with a lot of filters for things like location of item and watch items until sellers offer me a discount.