I have sold over 9,000 copies of FM in the last 3 years directly via my affiliate link, I know I'm not the largest with that number either. That of course doesn't account for sales driven by myself of people who didn't use my link but bought the game elsewhere or people who watched my videos before trying out the game on game pass for example. It's impossible to quantify exactly, but I do believe online creators across all mediums have a sizable impact on driving FM sales, if SI didn't think that was the case I'm certain they wouldn't do the Alpha access for creators they do every year.