Raphinha is very good at LW too, while Richarlison is poor at RW.
Kane & Son are the 2 best players out of our front 3, so it makes more sense to buy a player who can provide healthy competition to Kulu at RW.
Rich means we don't need to buy another back up CF... but he's a worse signing in all other aspects.
He is not "poor" on the right wing.
He has as good xG numbers (0.28) across the forward three positions, in fact he has higher overall player rating on the right wing (but less games) as he does starting as a CF or LW.
Left Wing: 2,720 mins / Centre Forward: 2,954 mins / Right Wing: 1,369 mins
He's not yet an "elite" striker, but we are not looking for one, nor would we get one to play second fiddle to Harry or Son.
Here is a superb article on him:
The data that shows Richarlison is evolving into a complete modern forward
Richarlison's metrics show he is equally effective for Everton on the left, right or through the middle — but could do with shooting more