Guardiola is immensely complaining about Rodri missing the game and that the referee sent him off anyway. Can't recall the foul right now, but I am sure Manchester City has someone on the bench who is just good enough to play instead of Rodri.

I don't know where you saw Pep complaining about Rodri missing the game, i've watched all Pep's press conferences this season and after the Nottingham Forest game, Pep was actually angry with Rodri for losing his head and getting sent off. Pep has been asked countless times if Rodri would be a big miss for City, and he accepted that he would be greatly missed, and of course that is true, Rodri is the best defensive midfielder in the world and City have missed him since he has been suspended and they will miss him on Sunday, but Pep hasn't be complaining, instead he said they will find a solution, which i'm pretty sure they will.
It is a big game on Sunday, and it is almost impossible to predict, Rodri is a big miss and i think Saka might also miss the game due to injury. City have a good run of defeating Arsenal, thus i expect it to continue.