Overall, a pretty nice delivery. I like your intensity and explosiveness. Your lower body action is very good. Something to consider is perhaps a slight increase in the height of your lift. I was thinking somewhere in the 4-6 inch range. It may aid you getting even more distance away from the rubber and allow time for you to get the lead hip really out there. At foot strike, your arm is definitely up, which is good, the ball is a bit close to your head. The angle of the inside of your elbow seems to be in the 60-70 degree range (a bit tough to tell since the frame rate doesn’t allow for a really clear look. Ideal inside angle being closer to 90 degrees. I think the couple of inches away from your head you may gain would help your external rotation of the shoulder and make your arm longer to release giving you more time to transfer energy into release during your unwind. A vertical ball has a lower moment of inertia than a ball that is held to either side of vertical. It requires less pressure on the grip which is another velocity aid. At the follow through you seem a bit high, but not seriously out of whack. Most of these comments are just picking at details. Perhaps someone else sees something I’m missing.
As a side note, your delivery looks a lot like mine did when I was your age. I was 170 lbs at 17 years old and sitting around 83-85. I had a similar arm position at foot strike and was told a few years later that changing it would have gotten me another 2-4 mph. In HS and Legion, I was a catcher most of the time between my pitching appearances. While that arm action helped get rid of the ball faster and improved my pop time, I was told it took something off my top end. I did change a few things later on but it didn’t really prolong my career because I was out of college by then.
Adding a few mph now would benefit you greatly because you are on the cusp of being above average velocity. Adding it late, like I did, only made me a force in the adult summer league Improve now and you could be playing some college ball.
Another suggestion would be to have your delivery from set position analyzed because pitchers throw more from the set in games, yet seem to practice more from the windup. One of those strange but true facts that should be considered when establishing future bullpen routines.