OK, there's a couple of things that jump out.
First, you are early extending (aka "standing up", aka "losing your spine angle") and flipping the club (left wrist is breaking down/bending through impact) as illustrated below. In the right picture, red shows positions at address, green positions at impact.
So, why are you early extending and flipping? Well, because you have to make these compensations in order to hit the golf ball. But what are you compensating for? In my opinion, the fact that your pivot (the rotation of your body, most importantly your hips) stalls well before impact. Once you stop turning, the only way to keep the club moving is to unhinge the wrists, straighten the right elbow and let the arms disconnect from the torso. The club head goes through and rolls over, left wrist and elbow must flex and you get the classic "chicken wing" follow through. All of these elements will also tend to make your club's sweet spot move more vertically and more to the left of your target line. The early extension is your subconscious's reaction to that -- allowing you to both shallow out and move your club path more (back) to the right.
So the most important question then is why are you stalling? Again, just my opinion, but I would say the simple answer is because you are not getting your weight forward enough. To get your weight forward, you have to move the hips laterally towards the target, and only once you have done that can the hips and the body and the arms all turn through the strike area together in proper synchronization. There is a lot of material on the site about this area, because it is so important. This is a good place to start:
Also look for the rest of the "Key #2" stuff here: https://www.youtube.com/playlist?list=PL9wzVgBx_LuTuTZOu3-SVM2m-Je3tRfqS
The more complicated answer is illustrated below.
I've marked in red the position of your left leg at the top of the backswing, half way down and at impact. You can see that it remains flexed to the inside throughout the downswing, though the amount of that flex does decrease. That means your left hip is staying in what is termed "internal rotation" all the way into the ball, which is not a good thing. Make a practice backswing and pause at the top. You'll see your left knee has gained flex and come inside your left foot. Now keep the knee in that exact same position and try and turn your hips. You can't really, can you? There's physical resistance. And that's what is happening to you in the downswing, I think. To deal with it, you are going to have to really focus on pushing that left knee outside the left ankle as you make the transition from the top of the backswing. You're also probably going to want to feel like you are keeping it flexed more and for longer during the downswing. The more you can do that, the more you can slide the hips laterally and the more you'll be able to keep them turning.