Maybe this season was never meant for City to become the winner, that is why we are seeing this late hour injuries in a critical time like this. City needs to pray that De Bruyne gets back to his feet before the clash with Real Madrid, if not they are out of the champions league. What a bad moment for them, I hope Pep will be able to make sure his team doesn't drop much points.
The international break often presents a nightmare for English league teams that are competing in the championship as it is today, player injuries are of course very likely to occur and in the end make the club will be very disadvantaged, because indeed their performance is affected by the injury of their main player who plays for the national team at this time, what you say is true, Last season the injury storm that hit Arsenal made them have to hand over the Premier League trophy to Manchester City when Arsenal were only one step away from achieving the trophy, but I don't think that will happen to Manchester City this season, although at the moment Manchester City have some injured players but they have better squad depth, So at least they have substitutes who do have the same level with as the main players and that is different from Arsenal who had less squad depth last season and even today.
De Bruyne injury, it doesn't seem too severe and reportedly De Bruyne has a groin injury so it may not take much time to heal, besides that I think all Manchester City players will be very ready to face Arsenal next week because after all Manchester City substitutes are also very worthy of Arsenal to watch out for.