As I said earlier a player really needs to be a star for his team to fix games because they're the only ones that will stay in the when playing inexplicably bad.
But skilled players can do it without making it obvious by looking “inexplicably bad.”
I recall, in that Netflix documentary, Hedake Smith talking about how he did this at Arizona State. He’d do subtle little things that the fans didn’t notice like delaying a pass for a split second so the D could catch up, or feeding teammates in spots where he knows they’re likely to miss, or just taking a step out of position on defense.
At the end of the day, it would look to the fans like Smith had a good game, ASU would still win (but not by point spread), and nobody had any idea that their star point guard was shaving points the whole game.