You use dair way too much on neutral, try not to since it is laggy and whiffing it means you'll get punished.
Your dash dance still needs work but it's definitely better, try to work on different lengths of dash dance and being able to move left and right while doing it smoothly(making the dashes shorter in one direction). Also try to incorporate wavedashing with your dash dance, it helps a lot imo, and remember that after a wavedash you regain all your options so try to always end your movement there so you can dtilt/utilt/whatever to cover unless you're searching for a grab or aerial.
You respect the edge too much, edgeguard or at least threaten them, don't go back in the center and let them in for free. Stay close and dtilt, short hop last second dair, fsmash, anything but make them scared not to sweetspot.
Never try to approach from above, I saw you do it a few times, full hop dair or whatever. You always wanna be under your opponent not the other way around.
Work on your ledge game, I saw you stay at the ledge without refreshing a few times, and just roll back in or whatever. Mix it up, learn to refresh correctly (Under the stage to avoid a gimp), normal get up is hella good if unexpected it has a lot of invincibility, ledgehop nair is good, ledgedashing and hax dashing can mix up too if they're waiting.
I personally hate marth dittos, it's yucky. The marth you were playing seems to know a few things so if you know him you can learn a lot from him actually. Basically aim to Dtilt to stop the opponent from dash dancing, they'll start throwing more aerials and you can now punish that. Try to search MU specific punishes since marth is so punish heavy you need to know what to do after confirming things.