-back knee collapse
Too much bend in the back knee during and coming out of the leg lift. It should flex a little, but not enough that the torso noticeably drops. Stand taller during the lift instead of curling into a ball, improve your posture and dynamic balance. Work on increasing the power of the back leg drive without dipping downward with the torso. Stay high and lead with the front hip.
-opening the front side early
Delay the opening of the stride foot toward the plate for as long as possible by showing the catcher the outside of your ankle as early as you can coming out of the lift, and for as long as possible during the stride to build momentum, to stride directly toward the plate, and to translate more power into the upper body later on through greater rotational torque. Initiate the trunk rotation from the back side. Some use the back knee or back hip as cues.
-body and stride leg lean going toward 1B direction (peeling off)
The upper body leans like this to compensate for a closed or cross body stride to get you back on target. From the angle of the camera, I can’t tell how severe it is. That front knee and ankle need to be vertically aligned during truck rotation. If not, energy is being siphoned away and you aren’t throwing from a stable platform.
-front knee collapse
The inside angle of the front knee should not get below 135 degrees. If the angle decreases, you can’t get your upper body over your front leg for trunk flexion, release, and follow through
-trunk flex inhibited by the front leg
Your chest is running into your front thigh and you are not getting over that leg until the ball is gone. Usually pitchers who over-stride or have weak back leg drive run into this problem.
Take on these points one at a time and in sequence.