Okay, I'm going to take a risk and say Phil Foden. Not the most overrated ever, but we as a fanbase definitely overrate how good he is right now because we mix it up with how good he could be in the future. His contribution so far has been equal to or lesser than many members of the squad but we talk like he's one of our key players. He's watched an awful lot of the last two seasons from the bench and yet has won two major awards over guys like Saka and Rice who are star players at their clubs. He's almost universally agreed to be better than Sterling, Mahrez or Jesus but his output doesn't really back that up at all, and I think he's more talented than any of them.
I say this because I can see us going down the path of the people who talk like Gascoigne was the best player of all time, and I don't really like the idea of him being crushed under the weight of pressure he didn't ask for.