Tbh I find all the talk about "needing a natural striker" completely old fashioned, always have. Goals are goals.
So long as you have people making the runs of a striker, who can score goals, like Salah and Mane whenever Firmino difts wide or deep, you're alright. Plus, Firmino isn't a bad finisher.
And actually when you watch Liverpool, this new 4-4-1-1 shape basically has Salah playing as a striker most of the time.