Hi! Nice choice in color, I'm just going to run you somethings that can really help! Or not.
1. Being aggressive at the ledge is really dangerous as doc, there really isn't a good situation where you should be doing a dair or fair from ledge. Dair has too much lag and fair has too much start up. If you want to be aggressive from ledge work on your invincible ledge dash into up tilt or down smash. Those will cover you the most aeria around you and are pretty safe if you space them well on shield. In general you should work on your invincible large dash, it's docs best option off ledge. Also put some time into figuring out how low Doc can go below the ledge and still snap on to the ledge with those magnet hands. Another thing If you want to have some fun learn the Super Stall!
2. You got to move man. Doc can be a slippery dude so work on your wavedashes, they need to perfect all the time if you want to move best. Don't forget to dash dance! The better you move the more intimidating you'll look and the more options you'll have. Doc doesn't have a lot of options OOS. Now I don't know if this was you being nervous but it's something you should be aware of, you really shouldn't rely on shield grabbing your opponent. It just screams that you don't respect their offense when you spam it like you did. You need to recognize "who" you can shield grab. Like that fox you played, your attempted shield grabs did more harm than good because he had solid shield pressure and you where ansy for it. There's nothing wrong with rolling or wavedashing in situations like that. Movement is better than shielding.
3. Approaching in neutral as doc. Let's face it man Doc can't run around and SH nair or dair like Fox or Falco. When approaching you have to mix it up every time, most of Docs moves can auto cancel out of short hop. One thing I like to do is to SH rising bair then waveland towards or away from my opponent or full jump rising dair over your opponent then any other aerial(other than dair again). Dair should only be used in situations where it will auto cancel. Once you've conditioned your opponent with options like that, then you can go for SH nairs cause it's a mixup! But when approaching with SH nair always go for the cross up cause weak nair can easily be shield grabed. Doc can be pretty creative once you put the time into it.
4. Work on a secondary for marth. That matchups not fun at all as Doc. You can lose to people who are way below your skill just because they spam grab and can time their f smash on your recovery. Or really do some research and learn what's best to do vs Marth.
5. Punish game. Stick to the guaranteed stuff until you know how to free style. You can't pick up a guitar and jam with the band until you know how to play the chords. So for now chain grab the spacies, wall out the sheiks and Marths with bairs and hit the lab hard. One day you can swag out but practice and knowledge will be your best teachers in the long run.
Hope this helped some, cheers!