Nobody Really

The relationship between Joey and Kaiba is due to a relationship he had with an extremely arrogant MTG player when he first started playing.

Yeah that is his inspiration for Kaiba's initial character in general. Though the show oddly enough has a bit of a juxtaposition with those 2, and it is hard for me to elaborate on but I know they have parallels going on and some key things that set apart their approach in life.
Also, you can almost just swap their hairs in some of their images and they look like the same model xD

Random trivia but: The card game in-universe was only gonna be a one-episode deal but the Shonen Jump readers got interested in it and so the IRL game was born and the shift in focus of the manga and anime towards it as well.... Regardless, Kaiba was always built up to be the main rival regardless of the card game's destiny as part of Yugioh. Not only did they tie the game at his debut in season 0, but entering an arcade, Kaiba actually had national top score rankings in virtually everything, alluding at him being an appropriate foil for the "King of games" that the main character was meant to become. Not for nothing the entire last season was actually a giant Dungeons & Dragons game themed on the pharaoh's Egyptian past, rather than the card game prominently.

Honestly loved the last season.