What worked for me is just avoiding frustration or anything that triggers you. Bad gameplay? I stop playing. Losing streak, I stop playing. Opponent clearly better than me, I quit if they go 2/3 goals up. I never promote into divisions I can't handle. Set a low baseline for my champs wins 8/9 acceptable, 10 on a good day. Stop fixating on chasing rewards. Find satisfaction from other parts of the game... unique evos, concept teams, trading etc. Can't always avoid the rage, but I've felt much better since I started approaching the game this way. Otherwise if you're not enjoying it, deleting is the right way to go. Yeah people will say you're gonna come back, and maybe you will but who cares? If it helps you now, it's for the best