I think you get impressed by pass completion stat percentages from a conservative passer of the ball in the most dominant possession side in Europe, and don't understand what you're watching. There we have it.
There isn't a single attribute Rodri has over Fernandinho besides height and strength, and even then he regularly gets done shoulder to shoulder, and put on his arse, in a way you don't see happen to Fernandinho, even at the ripe old age of 36.
Rodri is a glaring weakness in this side. In a key area of the pitch.