Zatchiel
a little slice of heaven 🍰
You have to recognize and accept your mistakes, because otherwise they will do nothing but haunt you in your future with the game. Unless you have countless hours to dedicate to practice, odds are you aren't going to always be on your A-game. Don't beat yourself up.It's not just getting flustered when things start going badly, it's also just beating myself up when I lose repeatedly (which I know is really stupid and that I shouldn't care so much about a ****ing videogame) and I'd have to imagine that really trying to work out a character as technically difficult as Shulk might lead to that. Admittedly, I did use him for a while, and started to get a grasp on him, but as I think I mentioned earlier I feel like I've been having to relearn the game ever since dropping Mega Man, and I don't know how difficult that'll be with Shulk.
Shulk does have a pretty demanding meta. Every game is going to feel like an uphill battle while you figure the character out, and that's necessary. Patience is probably the one thing that will help your progress with this character more than any other.
Learning him won't be a walk in the park. It might take months before you even feel comfortable using him against competent players.