Hey Riley nice guitar, very crisp sound. A big thumbs up.

Anyways looking at your ved, then thinking about the problems you suffered in the past and how they affect your playing. I may have an answer.
Throw your guitar strap away. Or atleast put it aside for a month or six.
Looking at that vid, it looks like 95% of your right arm movement is coming from your shoulder and 4.5% from the elbow. Only half a percent from the wrist and nothing from the thumb.
Now I suspect this is a result of your medical condition. I suspect you've also undergone some physiotherapy to help your motor skills.
So I want you to check first with your physiotherapist. Then go and get the lightest plectrum you can and only play sitting down. Fast Johnny Ramone type rhythms. Sitting will make you work more from the elbow and wrist, making it harder to get the shoulder involved.
That should help you relax that wrist a bit over time.
Also spend just 5 minutes a day doing chordal arpeggio's (not that shredder nonsense) like ballad chords that are single not picks.
That should help you get the thumb and finger joints working.

Throw that strap away mate, it's doing you no favours at the moment. Pick it up when you got that arm working good. Cos it is important to be able to play sitting or standing.
Check all that with your physiotherapist first though.

Once again, nice axe mate.