No, not entirely. Not having Rodri doesn't explain why they're losing almost all their games. In other words, Rodri missing isn't the reason they're playing relegation form. Rodri is the reason why they beat Arsenal to the title. Which brings me to the point. The biggest issue is that psychology is football is king. City are playing the exact same football, same movements, same shifts of play, same everything, but mentally when you're not there, it can undo every tactical advantage that you have.
They are mentally and psychologically shot.