@Kudemo
Hmm ok theres quite a few things you could be doing better vs d3.
1. When you want to edge hog, dont run off and side b. It gives you landing penalty which if you dont recognize the term i can explain that one too. You also want to calm down a bit when you're edge guarding, you're moving around a whole lot, but a lot of it is kinda unnecessary and sometimes gets you outside of a good position, giving d3 an easy time back. If d3 is at the ledge, i think the best place to be is really close to it so you can punish his getup attack with grab or usmash or somethin.
2. whenever you go for something risky, make sure there isnt much of the stage behind you. This d3 player didnt really capitalize on this, but essentially the more stage behind you, the longer the cg's (more % you take). Like sometimes he only did 1 dthrow and then a bthrow, when he could have done 2 or 3.
3. you should grab d3 a whole lot more, and i'm not saying to go upto him and try to grab, but after you cross over or have any opportunity where you can get a grab and he cannot, you should go for it. it allows you to get him into the air and then punish his landings, which leads me into the next thing to work on.
4. punish d3's landing better, especially landing with inhale. you wanna stand right under him, so he has a hard time deciding which way to inhale or if he wants to bair. both of these lose to shield->reaction though.
if d3 goes for bair, you can usmash oos to punish or dsmash, etc. if he inhales you can roll to the other side of him (assuming he's not at the edge, in which case inhale will push you offstage).
Another thing i wanted to note about inhale, is that if its from afar, you can punish it with laser, bair his head or grab (from the front, yes) but grab has kinda tricky timing (you have to grab while being sucked into him. essentially grab just has higher priority or somethin). You can also just jump over him and do anything. If d3 does it really close, just shine or jumpshine-> some other punish.Shield also stops the suction of inhale allowing you to retreat w/roll if you desire for some reason.
I could add some more tips for fighting d3, but i think for now all this should help you a lot, and i dont think its a good idea to try to implement a dozen things all at once.