I see a strong and athletic girl!
The issue that jumps out at me first is a DBSF (Drop the Barrel and Swing Flat) swing pattern. She is lowering her hands and leveling the barrel behind her shoulder as she is reading the pitch, before she launches the swing. This faulty leveling process is a time-waster, and is likely a big contributor to her challenges with fast pitching. This issue typically arises from the belief that the bat should be swung level to the ground, and may have been encouraged by coaches saying "swing level".
What we see with good swings is the hands staying near the rear shoulder while loading and reading location, and launching the bat on a diagonal plane to contact. The lower the pitch, the steeper the angle of the swing plane. Except in the case of a swing at a shoulder-level pitch, the hands will be above the ball at contact.
In the case of a DBSF swing pattern, we see the hands drop and then swing the bat forward. This is a lot of excess hand travel. In a proper swing pattern, the hands will travel in a fairly straight line from the rear shoulder to contact, turning the barrel to the ball (hands are the center of the bat's rotation).
