In the games, Geralt mostly wears brown due to his leather armor, as well as a smattering of red and blue in some of the textiles, like gambeson, shirts, robes, scarves, etc. These are normal medieval colors and would be accessible to the common person.
But in Netflix adaptation, he wears black and ONLY black, which is crazy because, black was actually considered a luxury dye in the middle ages because of how complicated the dying process was. And even then, you wouldnt get a true black; it was going to be blue/black, red/black, or yellow/black. It wasn't until the 17th century that true jet black was possible with the introduction of logwood from Central America.
But Geralt's clothing and armor in the Netflix adaptation IS a true black. And these aren't even clothes for any special occasion?? It's just his normal day to day wear. Like can you even imagine??? This random guy walks into town wearing the most expensive textiles you've ever seen and then says he's going to go fight monsters in them?? What a damn flex.