Again, I don't believe you fully understand how good MK is.
MK has no real bad matchups, he has even matchups at worst.
His recovery is the best and almost breaks the game in itself.
His nado pretty much eats most of the moves in the game.
Most of his moves are quick and have little to no lag.
His Shuttle Loop has an insane amount of knockback for a primarily recovery move.
All his aerials are amazing.
One of the quickest and a small character
His planking is unstoppable.
I could keep going, but there is no need. You can try to convince yourself that MK isn't broken, but he has no limit to what he can do to other characters. Hell, he completely shuts down some characters. There is a reason why he is top tier and is now banned. It took over four years for this to happen, so people have debated this.
It's good you have confidence but don't be overconfident. You will need to learn your limitations. Single-player has absolutely no correlation to how good you are.
But hopefully you can learn something at Hobo.
P4, go play CoD ya poopface.