Hey,
Note this is all just my opinion based on my own observations:
I used to main Marth in melee and I absolutely love Lucina and Marth in this game too. I’m a new Mewtwo main thorough so I’m excited to discuss this. Marth’s want to use superior movement and range in order to keep pressure on the opponent while remaining safe themselves. They prefer a ground game and have the tools to dish some very heavy punishes. However they aren’t great at dealing with in your face pressure and are vulnerable once they leave the ground if they aren’t careful with their spacing. And as a bonus their recovery is poor in terms of mix-ups and even survivability compared to the other High tier characters in the game.
In a lot of ways they play a lot like Mewtwo which is probably they’ve given you trouble.
You want to be patient. Bide your time with tilts, jabs, superior movement and spacing, and shadow ball. Always be conscious of their range. Keep your SB charged as it tends to make think people think twice. But only use it when you’ve trapped your opponent in a position where they can’t avoid it.
Once you have the opportunity you have to be able to strike relentlessly.
Now for some things I’m less sure about:
They favor down tilt and dash attack as approaches. I’m not sure but I think you might be able to fair their down tilt approach. And I’m also not certain but I think mewtwo’s forward tilt output ranges Marth. I’m also fairly sure his bair does so you’ll want to incorporate attack canceling’s instant bair if you haven’t already.
Hope this is moderately helpful and I’m looking forward to the conversation and getting better together!
