Not sure if I know what you're asking, b; with your opening question?
Not trying to convince you, or anyone; if everyone believed Manning GOAT, who would I argue with? I get it. My older brother refuses to put Brady in his Top 10, that's how much he hates him...and, he makes some very valid points; however, my younger brother says he's the GOAT, Manning being his favorite player ever, like you. And, I'm in the middle...knowing Brady is Top 5; and knowing Manning is the GOAT...and, ive looked at it from every objective angle I possibly can. They were drafted into two TOTALLY DIFFERENT CIRCUMSTANCES...and never, in all my years of being a superfan of the game of football, and studying it, have I come across so many "what if's" whenever discussing Manning vs Brady.
I have always likened their rivalry to Ted Williams vs Joe DiMaggio. DiMaggio, while one of the all time greatest to ever live, he played for the Yankees...Williams was greater.