Finals are usually neutral and this time the Manchester City vs Inter Milan match will be held at the Ataturk Olympic Stadium, not at Manchester City's home ground. That's how I see it in the schedule that has been laid out for them although I also think that it won't be a problem at all for Manchester City and also Inter Milan as both will be looking to win their last game in the Champions League this season.
Manchester City is a talented club and they don’t care if they are playing at home ground or Away, I don’t always see any difference in Manchester city performance either they are playing at home or away, but it won’t be easy for Manchester City against inter Milan, because inter Milan is also a dangerous club, it’s won’t be a easy match for Manchester city just like the way people have been saying that Manchester city is going to win. Actually pep Guardiola will want to win three leagues for Manchester city this season and he has successfully won two, remaining one so am sure he will do everything possible to win the last one.
You are right that Man City always has good form wherever they play. And this time the Champions League Final which will be held in Istanbul, Turkey, namely at the Atatürk Olympic Stadium, will not have any impact on Man City but neither will Inter Milan. Because this is not the home of Man City and also Inter Milan. So this is a neutral place for both.
But for one of your players, Man City, namely Ilkay Gundogan, the location for the Champions League final is in his parents' hometown. Although he was born in Germany but his parents have Turkish birth. So going to Turkey with Man City definitely brought a different atmosphere for him.