I watched the middle one and only the first few minutes and there is enough to do based on that so let us start off with that because there is too much to change simultaneously in those throws to try at a single time. Don't be discouraged because you will see improvements. For starters changing form is much easier to do with taking slower steps.
You are not getting a proper weight shift forward because you raise the right leg from the hip joint in the last step. That makes you take a way way too long of a plant step. The right leg is keeping you from shifting to an uproght position as the disc rips out. You are also spinning out meaning your body rotates in a continuous movement making you turn toward the target too early moving the disc on an arc instead of a straight line. The way to do things is to move the disc from the reach back to the rip with a three stage movement of the body. The first can come from momentum alone at such high speeds you were moving in and with slow steps with slight left leg push. The first stage ends when the navel and face point ot the left side of the tee pad and the right leg needs to brace or stop relative to the grund using as much tension in the muscles as possible once the heel is on the ground and the ball of the foot is up. The disc is around your left side. The second stage has your body almost stopping and the arm moving the disc to the right side or beyond depending on the style and your body proportions. The arm is moved forward from the shoulder moving straight at the target. The third stage has a sharp left leg push forward and depending on the style possibly pivoting first on the left leg ball of the foot and twisting the knees to the right or not, then loosening the right leg and pivoting on the heel with the hips twisting to the right and shoulders turning even farther right, elbow straightening wrist snapping forward and the disc pivoting. The final step length changes with running speed but normally about shoulder width is ok for slow control throws and a foot to two longer is fine for mst shots. Spagats are not.
Mind the path the disc takes after you shift your weight forward the reach back should be as high as the rip point for a line drive for accuracy. Distance shots are anther matter. Once you master not throwing high and having the disc not stalling out you could add power by reaching back much farther. It can kill your balance at first and reduce distance so it could take months to gain power. Then you will add so much distance that there is no turning back from that technique so persistency and regular field practice is mandatory. The way you reach back farther is to turn the feet farther away from the target (up to the heels pointing at the target in the x step and landing of the plant step), turning your back at the target and turning the shoulders far back enough to allow the head to turn away from the target and the arm reaching as far back as you can or almost. The right shoulder should be farther back than the left in the farthest point of the reach back.
Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.