I think it is an unfair comparison to compare a fully rendered drawing by your dominant hand to a doodle with your non-dominant hand. This is why I compare rough sketches I made under approximately same duration. I cannot be arsed to correct the anatomy, make it less ugly, and polish it.
I thought doing it on my phone with finger will make it easier because I do not need to hold a stylus, I was wrong. I must train my left hand.