I agree, tbh that quote is made up but that's how I imagine Southgate. He is as you say very balanced, but he also has a personality in that thoughtfulness you mentioned. And yes, I believe he does have a set of lucky pants, and he'll be wearing them tomorrow.
I think he has benefited from getting a young, talented squad without all the pressure of expectation. That has helped him. I don't think he would've been given the job if he'd inherited the side of 12 years ago. IF this current crop of players can grow under him, then he will grow himself in becoming a manager who can manage a team of worldie players. TBH he's in a very fortunate position that most England managers don't get.