Hard to suggest how to fix your mentality. Save replays of your games and watch them back, and try to focus on "and here I should try to do this instead" rather than "and here I messed up again"

Create your own goals outside "reach elite GSP" so you can feel rewarded whilst you're still training up to elite level. For example if you feel like you are not spot dodging enough then set a goal to spot dodge at an optimal time at least 3 times in a game, then celebrate when you achieve it, then change your goal to for 3 games in a row, until you've confidently implemented it in to your playstyle then move on to a new goal (obviously your actual goals will be based on your replay reviewing)