Axel,
A coupe things I would point out. Your bow arm really never stops on target. If you watch closely, as you draw, the bow hand goes above the target (that's OK) but when you begin to depress to the target, you NEVER stop ON TARGET. You just float through in a downward motion and it actually accelerates downward. Try to stop and hold on target. Looks like you've developed a habit that will take concentration to change.
Second, and contributing to the bow arm problem is your collapsing release. Watch the part of the video where you are filming from behind. You come to full draw with your elbow moving to the left in the picture. Before you release though, watch that elbow move to the right. That is a classic collapse. I find it very common in those that shoot what is called a dead release. That is not allowing your string hand to move. What this does is take any tension out of your back and when this happens, the shot is ruined for all intents and purposes. Many can shoot a dead release well but hardly any can do that WITH a collapse.
That loss of back tension also contributes to a "floppy" bow arm. A good archery shot MUST be powered by your back muscles and when they are out of the game you have inconsistent shooting.
If we were "face to face" I'd recommend a form master -- I make them and give them to my students. Some work with that contraption will pay off! Good luck, and keep videoing yourself and check on your progress. It's hard to feel if you are doing it right but fairly easy to see.