That technical stuff is really practice. It's not some magical thing. It's hard work, like an athlete, in a way. You just have to practice how to embody this character. If I'm playing a character who isn't like I am, it can take months and months.
You don't want a lead acting role if you're not the one that's supposed to be playing it. I'm perfectly satisfied with the career I've had.
I did have hesitations and just knew that if I made the story the main character and really worked on that to fulfill it in a very personal and soulful way, that all the technical stuff about playing him would become secondary for people watching the movie.