Football (soccer) players are hard to gauge because the positions are so different. There are the forwards who attack, and there are a lot of those... Maradona, Henry, Larsson, Nistelrooy, Rooney, Cruyff... I can go for days. I still think Maradona was the best athlete because he could straight up play while high on coke.
Midfielders are tough because theres attacking midfielders, and defensive midfielders. Best attacking midfielders? probably Ronaldinho or Zidane. Best defending midfielder? Probably Socretes, because he was able to do a shitload of weed and somehow be amazing.
Then defenders are even tougher, because they dont have real stats. I'd say Claudio Gentile is the best because how the fuck are you going to score if you have a guy rubbing his nads on you all day long? (thats what he did. he was nicknamed "genitle" for a reason) All I know is that if Maradona couldnt score on him, nobody could lol.
With all that said, I would say Beckenbauer was the best ever because he could play all the field positions. I'm not even going to talk about goalkeeper, because thats a whole different situation.