From what I think I’ve learned over the years, there shouldn’t necessarily be a whole lot of difference between the way sidearmers are coached versus any other pitcher.
Some basic ideas that every pitcher needs to work on:
(1) Strength & Conditioning for pitchers…especially pay attention to strengthening decelerator muscle groups. They are often neglected in pitcher’s weight training.
(2) Maintenance of a repeatable delivery and a repeatable release point. Whatever your delivery looks like this starts with a consistent sense of balance and posture at beginning of your delivery, continues with getting your momentum entirely focused toward the target, correct sequencing of events within the kinetic chain…i.e., hips rotate open around foot-strike/shoulders rotate open as late as possible after the hips.
(3) Good nutritional habits to support your strength & conditioning work.
From the clips you provided I thought you looked very good. You didn’t mention how you got hurt, or what part of your anatomy is hurt…do you believe that some particular feature in your delivery caused your injury, or was it more to do with a lack of strength & conditioning to properly support your delivery? Or, something else?