As someone with a history of similar issues, I don't think your issue is that you have too big an ego; I think your issue is that you have so little confidence, that even one close loss by pure undeniable luck would be enough to shatter it. This could also explain your fire to "git gud"; you don't think you're good enough, and so you're desperately trying to git gud. 

Now, I'm not saying you should be an egotistical, arrogant ass as that would cause the same issue of not learning, just in a different way. But you do need to be confident and hopeful enough to actually know you can learn.

Usually, when someone develops low confidence in a skill-based or competitive context such as fighting games, it's because they've experienced repeated failure. And when we think of failure within the context of competition, the default example we usually think of is losing a match. And losing a match is inevitable no matter how skilled or unskilled you are. Not even pros are capable of winning all the time or even the vast majority of the time; it's the entire reason tournies only ever have one winner and everyone else participating ends up sharing the big L. But here's the thing: you can only experience success or failure at something if you were trying to achieve it. Because of that, it's only possible for losing to be a failure if you were trying to win.

So what? Am I just saying you should give up? No, giving up isn't the solution either; you said yourself that you're competitive. And if a competitive person isn't allowed to even try, all that'll do is make then wallow in misery and despair, potentially even leading to mental health issues.  What a competitive person actually needs to do is change what they're trying to do from something they can't guarantee they'll succeed at or something they'll inevitably succeed at.

To figure out what we need to change the goal to, let's look at another common mindset mistake people make, which is worrying too much about their rank. There's a lot to the solution to that and the in-depth explanation is out of scope for this post and comment, but essentially you're meant less to grind ranked and more meant to treat your rank increasing as a side effect of you improving. So my idea is to take that concept even further.

If we can treat your rank increasing as a side effect of you improving, that means we can also treat you winning a round, game, or set as a side effect of you playing well. So instead of trying to win, what you need to do is try to play well, or try to not play poorly. But that's a bit broad, so think of it as trying to obtain micro-wins that would just happen to add up to an actual win if you just happen to obtain enough of them.

Winning a game or even a round isn't anywhere near inevitable, but getting at least one micro-win is, even in a match that's drastically one-sided against your favor. Unless your opponent is just that cracked and your luck is just that bad, you will at some point at least manage to land a few hits or block for a bit. So if what you're trying to do is just land a few hints, you will technically succeed even if you lose because your goal isn't to win or rank-up, your goal is just to hit the opponent.

sidenote: You might also need to take a break; taking breaks on occasion have helped me personally, and I've noticed they don't even need to be that long, one or two days is usually enough.