Contact your target country's local consulate with your product specs and order size. They'll connect you with vetted manufacturers for free because their reputation depends on quality. The Portuguese consulate example: leather sneakers, 200 units.
Chapters
This is the biggest hack to find the best manufacturers in general, period. This is such a good hack. Say you're looking to produce a pair of sneakers in Portugal. What you're gonna wanna do is call your local Portuguese consulate and tell them, hey, I'm looking to manufacture a pair of sneakers. The ideal quantity would be 200 units. I want it to be made outta leather. They're gonna make sure to connect you with a manufacturer that won't let you down, or else it's a bad look on their country and they're losing out on business. And they have a list of manufacturers ready to go to give to people who consult with them on these kinds of things, and it's completely free of charge.