If you don't have a reaction time, work on getting a better one. Playing Robot Unicorn Attack actually helps a little bit #Erasure
Lmao, I actually agree with this.
Even though you only use 2 buttons in RUA, that's usually not more than what you'll need in brawl either. And it goes FAST! When you're getting used to react to new situations more like it's a reflex, having certain "execution habits" ready for each situation that you know is a guaranteed hit if you're fast enough, it can often turn the tide of the game.
But of course the "habit" has to be safe. You don't want to crash in a wall in RUA, either. One mistake and you're dead, so you'll have to know the spacing perfectly, as well. Being able to react without thinking, developing legit reflexes that makes you win the trade and keep a better momentum to the next trade in brawl is pretty similar to RUA, imo.