Counter
Your Marth is not bad; you do play kind of like a Melee Marth, you should really watch for openings for your F-smashes and Up+Bs instead of using them when they usually might not hit. The Up+B especially is very punishable; your opponent will look for these vulnerabilities and attack (you kind of got hit alot.)
Your airdodging is very good, but it kind of stopped after you lost your first stock (SD? Try not to do that.) When you stop the airdodging and commence spot-dodging, you could definitely add some defense (and offense) to your game by Countering every once in a while when your opponent thinks you're going to spot-dodge. Don't become predictable and try to use Dancing Blade as a quick punish and a way to avoid damage degradation.
The F-smashing is mostly fine; that's a great move, but it does become a tad predictable. Integrating every move (this is more fundamentals, your advanced game is already very good, the SHFFd fairs were technically proficient) will help your Marth become less easy to punish and less easy to read.
Also, may I ask how you practice? It's very easy to tell you practice alot (you don't just pick up Marth and SHFF fairs) so if we know how you practice, we could tell more about your game and maybe help you improve it.
Also, do you watch many tournament videos of Marth?
Torn