I'm not talking about Africans or traders or African traders specifically btw just non white people in general. Of course you're right about middle men being used for trade, and inland areas being harder to profitably access, but my point is that non white people in Europe (which includes the polish woods lmao. Idk if the Romani peoples had made it to Poland at that time but if they did they would certainly be chillin' in the woods) were certainly not as rare as you think they were, and historians have confirmed this.

Also, Witcher is ultimately a fantasy series so it's up to the creators to decide whether or not the fact that it's based on a story that a polish person created means that it's a representation of medieval polish life or just medieval fantasy.