A dumb idea that i have is that all the sports/hobbies in the Yugioh world are actually as dramatic as the card games, we just don't see them because we exclusively follow the POV of game nerds. Like, people that really like Soccer can do superpowered attacks like in Inazuma Eleven, but Yugi doesn't like sports so we don't see that.
Tristan seems pretty boring, but that's because we don't see the motorcycle-related spy thriller that's also one of those deliquent manga he gets involved in off-screen; somehow, it is the missing link that leads directly into 5Ds in the future
Tea goes to the USA and quickly becomes the protagonist of a Josei manga about dancing, with murder, betrayal and yuri undertones, but you need to go buy a diferent magazine to read about that unfortunately
Mokuba is probably the rival character to another protagonist in a anime about either Capumon or computer games in his free time; he's less unhinged than Seto in that role but probably even less likely to admit he has a crush on said protagonist
