The best way to improve is to just keep getting bopped. That is part of what it means when you're a buster.
I remember there was a long time when me and my best friend (who's way better than me) were (and still are) playing at least 2-3 hours every day. And I would get 4-stocked 30 times in a row before going to bed every night. But you learn. Now, when I get in a situation where I've SD'd twice and he's KO'd me once, and I'm about to get 4-stocked, instead of giving up and preparing for our next game, I put on my game face and push it out. If he keeps playing well, usually I can take like 2 stocks. More often than not, he'll get worn down and maybe SD twice, then I'll kill him once, then it's anyone's game.
My dad's been a running coach/personal trainer all my life, and one of things he says when you're in a race is that there's gonna be a little voice in your head that says stuff like 'you can't do this' 'it hurts, it's hard'. What you gotta do is stuff all that stuff in an imaginary box and sit on it. Then at the end of the race, you can unleash that stuff and use it for fuel. This is part of what 'no johns for life' means.
You gotta be like this: when you play someone worse than you (and hopefully win; that's my problem), it's friendly. When you play someone better than you, you learn so much - that's you're training. It's gonna be delayed gratification. As with most sports, there are diminishing returns. You will rapidly be able to beat casuals, but you're gonna make a list of ppl better than you, and tackling each one is gonna be supa hard.
Enjoy