Hi William,
There are a couple key relationships that help a player get more open. One is getting used to the body position at impact. In order to have the body open, the spine has to be rotated to the right at impact. (https://www.golfsmartacademy.com/golf-instruction/presetting-spine-rotation/).
Secondly, if you look at the position of you at impact compared to the big rotators, notice how low Collin's right shoulder is compared to his left? Can you film a video of you doing the drill - presetting spine rotation? We want to see if the big barrier is more from the body position or from the arm timing.
PS - for someone not very open, I really like a lot of your arm movements.
Happy Golfing,
Tyler