I'd say we cant really rate your Marth based on this video because of the fact that your skill is clearly dominant over the people you faced in this crew battle. So it looks like everything you do is almost perfect.
To get better rates or to see what to fix, you need a video where someone is in the same range of skill as yourself, so that it requires you both to go all out.
From what I saw though, you need to wavedash out of shield to grab or w/e, I noticed you tried to grab when IC's spaced their fsmash and you missed, this shouldnt of happened if you did wavedash out of shield to grab. Also, you almost always do this one thing, you dash towards your opponent then wavedash back then jump or fair. You need to change that up a bit, as it was pretty predictable watching you do it almost everytime, just mix it up.
Your Marth is looking good, but don't expect heavy detailed critiques from a video where you look almost perfect. We need a video where you're working harder and getting a challenge to get the win to look at, to better critique you.