The match against Manchester City can not be used as a reference because it is only natural if Chelsea loses but we can also see Chelsea's overall performance and it must also be admitted that Chelsea will not be easy with their new coach this season everything will start from the beginning and Enzo Maresca must go through a process that is not easy.
In addition to what you said, the opponent itself is still quite strong this season, namely Manchester City which is still well coached by Guardiola so it is quite natural that Manchester City can win when facing Chelsea whose team condition is being rebuilt by its new coach. This season may still not be easy enough for Chelsea to develop, but I will see how Enzo Maresca does his best for Chelsea in order to be in a better position in the final standings. But for now there are still many things that Chelsea will try and will be gradually improved by Enzo Maresca.