I think it is Brady easily. What Brady has done has never been done in football. He has had two hall of fame careers if you take his first 10 years - 3 titles, 2 SB MVPs, 1 league MVP and then his second ten years - 3 titles, 2 SB MVPs, 2 league MVPs. He has been player of the decade for Two decades in a row at the most difficult position in sports. He has 6 SBs most of any player ever. Jordan is 5 less than Russell. Heck Robert Horry has 7 titles for that matter.
Brady's achievements in football are so much harder because of the injuries and single game elimination. People always mention how Jordan never went to a game 7 in the finals yet Brady played in 41 games 7s and won 30 of them. Brady went to 9 Super bowls. 4 more than Elway. Jordan has 6 finals total. Russell has 13, Magic has 9, LeBron has 9.
Brady started winning right out the of the gate with a 5-13 team. Jordan took years to win while he waited for the Celtics and Lakers to get old.
Jordan is just a 6-8 year period which was fantastic. Brady has been going for 20+ years in a sport where the average career is 3.5 yrs.