First of all, welcome to the Board. We have a history of welcoming thoughtful and polite posters from other teams' fan bases.
Agree re Reid and BB. BB also did it early in his career, first with Parcells and then on his own with Brady 20 years ago (he also did a better job with the Browns than he gets credit for). Belichick was 48 when he won his first SB as an HC and his sixth when he was 65. Reid is 62. So not likely he'll be in that discussion. That said, every true Football fan was happy for Andy Reid when he finally got the big prize. And you can make a reasonable argument that BB and TB kept him from getting it a little earlier.
As for Ben and Brees. I'm a big fan of Brees, not so much of Ben because of his off field stuff.
But, my personal feelings aside, there is something to be said for doing it year in and year out over a couple of decades. Brees has put up awesome numbers, surpassed only by Brady...but has only one ring. Ben has two rings and has been a force for a long time.
I'd be willing to say that there is very little doubt that, after a few additional productive seasons, even without another ring, Mahomes will surpass both of them. I just put a lot of value on consistency over time with a changing cast of players (Mahomes' contract has been very cap friendly).