6 iron swing - contact inconsistency

The down the line has a lot of really good elements, so let's focus on the face on for where we might be struggling. When it comes to consistency iron contact and more compression, I like to look at the low point line. From the face on view, looking at a line after impact and trying to get the left leg, left shoulder, left hand and club shaft in line just after impact. If we look at yours, we can see that both the left shoulder and the hands are back of the hip. This will cause fat/thin or spinny quite easily. Depending on which you are more comfortable with, you can work on your upper body "covering the ball" better. Or you can work on some release work, but it looks like most of your issues are from delivery position to impact. I'd start with lead foot low point drill to see what you feel is the biggest difference. https://golfsmartacademy.com/golf-instruction/lead-foot-low-point/

Glad you're enjoying it! Let us know how you progress 👍