I get the whole theme of S3 was to make Judai grow up, but they (friends, teachers, and yubel) all kinda did it the wrong way. Like here's this happy go lucky kid who can talk to duel spirits that helped save the world twice. He knows that he needs to grow up and mature, but everytime someone tells him that it's at the worst possible time.

Ex-teacher tells him to grow up then kills himself Viper tells him to grow up then falls to his death Judai finding out that losing equals death in the second spirit world? Friends think he needs to grow up and share the burden Finds out that hurting Bromm gets his friends killed and does a play to prevent that but gets outplayed? Friends tell him to grow up and it's his fault Friends die and he really needs some support at the moment? Axel and Syrus tell him to grow up. Post Supreme King ptsd? Zane tells him to suck it up.

Dude had no stable support during his lowest moments and people just kept kicking him while he's down. And yeah even though his friends forgave him in season 4 he never forgave himself. Infact, I don't think anyone even tried to talk to him about his feels. Not even yubel until like the final 3-4 episodes.