Mate, Pep said Walker wasn't capable of playing the inverted FB role, even though Kyle publicly disagreed. You're conflating two different disciplines. Rico starts as a RB, forms a double No 6 pivot & when we're attacking he becomes a No 8 & even a No 10.
I absolutely hate the inverted system now. It's been totally sussed out, yet Pep keeps persevering with it.
As I said in my last comment to another poster, when Rico inverts, the right CB covers RB, the left CB stays central & the LB covers the left. The No 6 is supposed to drop into defence on defensive transitions to make the four.
It isn't Rico's job to cover RB until he's recovered his defensive position. He can't possibly be in two positions at once, hence the opposition working this out & hitting rapid counters into the vacated channels.
I stopped looking at our FB's & wingers last year when it became blatantly obvious the opposition had figured out how to counter our inverted system. Well obvious to everyone apart from Pep it seems.
We need to stop blaming the wingers for not beating 3 men each when left isolated, & to stop blaming Rico for not being at RB, when his unique position requires him to attack centrally.
It's our inverted RB system at fault, not the player tasked with operating there mate.