Looks like warmup serves to me, but now from 5 on.
Your left leg clears the court by one inch. You don't spring up into your strikepoint with powerful thrust from your thighs.
You serve from waist up is as good as it get's.
Looking at waist down, you put no effort into it.
I'm 63, I don't have nearly your upperbody serve motion, but WITH a sprained ankle and twisted knee, both my feet come off the ground by TWO inches, and I end up almost 3' inside my baseline if I'm trying to serve fast.
Why don't you use your legs? Look at vids of Sampras or Roddick, Stich or Korda. Their feet are NINE inches off the court, at contact of the ball. Your's are ONE inch, mine twice as good.