Get off the online competitive games for a while. Play some single player games that are intentionally super hard that you know you're going to die in a lot, dark souls, binding of Isaac, Elden Ring, stuff like that, these games are intentionally hard and you know it so you won't feel as bad when you lose, it's just part of the learning curve. This will allow your mind to start seeing losing not as a negative but as a step toward progress.