What I see is that back leg is always straight and stiff. You don't use your knees in your turns.
Not once did you initiate a turn with the tip of your board. They are all skidded or mostly skidded turns.
You can tell some of this as your board edge really is never off the ground. Hence all skidded turns and you bleeding off speed. Not being able to keep going faster.
You really need to start your turns with that front foot. You can tell when your carving you will see that very thin hard groove behind you after your turns.
Hope this was the type of info you were looking for.