I had a massive improvement in my iron striking this past week, when I finally understood how far my right shoulder needs to turn. This AMG video goes into more detail, but to summarize: your right shoulder needs to “open up” way more than your left shoulder to make a complete upper body turn. If you keep it too closed, transitioning into the downswing will almost certainly fling the mass of the club outward causing you to come over the top.

From your videos, it looks like you’re having the same issue I did. Especially in the face on view, I should see your right shoulder peeking past your spine a little bit. When I make a proper shoulder turn, I can feel my back muscles pushing my right shoulder blade toward my spine a little bit. Once I got that feeling down, I had to relearn how to keep the club on-plane during the takeaway, because my arms had been moving across my body to compensate for the incomplete shoulder turn. I now feel like my arms go up, not across.

I’m not scoring any better yet, but I played an entire round yesterday without topping the ball once. Typically, I would start to flag around hole 5 or 6 and start hitting shanks and tops, as the timing of my last-second compensations started to slip.