I don’t use equation to determine his ability. Yes, Liverpool won the league. But I watch the games, and he offers little that many other less heralded players could not come in and replace. You don’t need XI top players to be a top team. Liverpool have some of the league’s best players in other positions. Including the attacking third. Firmino needs to just largely do his bit in terms of effort and pressing, and if he’s moved to, actually contribute something every now and then. That isn’t the limit, or even close, for a ‘number 9 centre forward’ in a top team. He’s more than one level below his fellow forwards, yet has conned people into claiming he’s just as good.
Take goals away, and he is still far less contributory than both Mané and Salah. They are more involved and better in all phases of the game than Firmino.