If I didn't say it, I will now. Stop the throw from the left pec. Just reach straight back and don't throw so hard.
Your main goal with this standing throw is to find snap, learn to recognize when you hit it and when you don't and to hit it repeatedly.
By trying to throw hard, you'll just end up losing the concentration you need.
The disc is coming out early, some nose up, so you're not keeping the disc in close to your chest long enough.
Try this - Stand still - shoulder to your target and just to a reach back and pull through. No shoulder, torso or hip rotation. See if you can keep the nose down and find some snap. Keep that disc close to your chest all the way and then when the disc passes your chest, keep the disc against your forearm until it's down near your wrist, then let it flick out.
Once you get that snap you should be able to throw the same distances as in that video with ease.
Remember - focus on straight pull, close to the chest and nose down. That's it.
Oh, you don't need to bend your knees so much. Just a tad. Stand straight, lean forward until your chin is over your toes, then bend your knees until you feel balanced. Then throw