Yeah, I can’t say I see too much resemblance. Williams never came close to losing himself in characters the way Sellers did. I first Dr. Strangelove when I was about 12 or 13 and thought that he only played Mandrake. Had no idea he was also the President & Strangelove!
And Williams knew who he was, he was married a few times and had kids. Sellers felt so identity-less he struggled to ever even maintain a relationship.