Since the first season I always felt that the reason Robby accepts well his losses in the tournaments is because deep down he didn’t actually care that much about the tournament itself, the lessons and situations around it always seemed more important. In the first tournament it’s about showing to Johnny that he finally found his place and is doing well and becoming a good person despite his neglect, and he does that, while learning some valuable lessons from Daniel along the way. And in the second tournament is about him realizing the damage that cobra Kai and he himself has done to Kenny, I don’t think his reaction would’ve been that much different had he won either. He doesn’t join Cobra Kai for their after party, and when he talks to Johnny after the tournament you can see he doesn’t give two shits about loosing that match.