Manchester City's loss against Brighton is really challenging and difficult for the team at the moment. The way Manchester City is currently playing, they are unable to play with their best performance in every match and are failing. Losing against Brighton is really sad for the team, I think Manchester City may not be able to overcome their weaknesses, moreover, Rodri's position may not be filled by another player. In the absence of Rodri, Manchester City is facing many weaknesses, so Pep Guardiola will have to use a different strategy at the moment. Since Manchester City is currently not performing well, however, Manchester City lost points by losing this match. Due to losing this point, Liverpool has now moved a long way forward in the points table where the gap between the two teams is 5, Manchester City will have to face a lot of challenges to capture Liverpool's position now.
I think that the major cause of the reason why Manchester city are struggling right now is because of the absence of Rodri, and just as you rightfully said, if a player of same quality comes into this Manchester city side, things will go back to normal, but the major problem here is that Liverpool are running away with the tittle, though five points looks massive in most football fan eyes, but I don't think it's that big because if Liverpool lose two straight games, that five points advantage would be over, and besides the season is still fresh, their is still a very long way to go, but before then, if Manchester city still wan to win this year English premier league title, they just have to start ranking up the winnings, because dropping more points right now wouldn't do them any favour at all .