The ONLY Drill Beginner Golfers Need to Hit Straight Shots
Every good shot has a punch shot in it. Developing a strong punch shot will develop your full shot. Look at 2023 masters winner John Rahm, his full swing is basically a punch and he trained his game learning punches.
This drill will also teach you perfect ground contact. The ground contact should slow down the momentum of the club so much so that your finish does not come above the shoulders. You should not be stopping yourself, that should happen from the ground contact.
I do not agree with the setup and the hand position suggested at impact, but the concept of developing your punch will ultimately lead to significantly better contact with your irons.