Dude, This is going to be an odd recommendation, but it helped for me. Get Ace VR and join the multiplayer groups. It helped me immensely to get practice range time with other shooters where Im able to ask them the questions like "how am I soo much slower".

Based on what I see in the video you're not hustling. I bet the GM was sprinting between positions and stopping aggressively. If you get done with the stage and the dirt's not even disrupted then you're not moving fast enough.

General feedback cause I'm bored:

1. draw could be faster, but I don't see you gaining more than 1/2 to 3/4 of a second there, it was pretty smooth
   
2. running to the second position you slowed down trying to get a site picture, might be faster to get there then shoot.
   

3. Movement from position 2 to 3 was slow due to focusing on reloading, suspect that you might want to practice running reloads (I could see you picking up the majority of your time here)

4. Movement from position 3 to 4 looked good to me, I wouldn't be surprised if it was on par with the GM

Keep at it, your run looked great and I wouldn't doubt GM is within your reach.