Well,

If you choose store is “DE”, you need to check the node (returned in …/countries/list endpoint) for suitable value for other parameters (country,currency,lang). You need to use them in pair, for example …/products/v2/list?categoryId=4209&country=DE&offset=0&store=DE&sort=priceasc&sizeSchema=US&limit=48&currency=EUR&lang=de-DE.

Regards.