Look at the penalty the RS gave away against Napoli and tell me diving isn't massively important to winning matches. I personally think that Robertson stepped across him and fouled him but it is never ever given if he doesn't throw himself to the ground in a way that convinced the ref. To me that is a refereeing problem, the foul should be given whether he falls or not, but diving effectively is what gets Napoli three points. And VAR did nothing.
Teams that don't sell fouls will be worse than teams that do. Richarlison knows this and needs to just get better at the con job. And again this can only be fixed by the FA/UEFA/FIFA so our players should just do what they have to as shameful as it is.