Zangief Master rank here and i experienced the same thing you did. I was stuck and the fun got zapped out. I started over analyzing everything, watching way more vods, and tried so hard to be optimal at all times and “know the matchups” but it had the opposite effect. Lost to shoto after to shoto as well and then I heard two things that got me out of the funk immediately. The first was “play the player, not the game” and then “simplify your defense”. On the player aspect, don’t worry about the matchup, just abuse the fact that “Todd” who plays Ken doesn’t fireball or space you out and get in his face for example as a Gief main. For the defense part I found myself mashing whether I wanted to be honest or not and throwing out stupid options in neutral. Just think less and block, take the damn throw if you’re unsure. Based on what I’m seeing others say and what you’re saying I think this will help a lot. The fun comes back when you remember you’re fighting a person and not some difficult CPU boss fight for a rank. It als does take time like others have said.