My app isn’t a game app, but iOS 18 always enable Game Mode for my app automatically. I didn’t find a switch to disable it in Xcode.
See also https://forums.developer.apple.com/forums/thread/739387 w.r.t. LSApplicationCategoryType.
How to disable Game Mode for my app?
Game Mode is opted in for some existing applications (applications that haven't been updated for iOS 18) automatically depending on a number of characteristics. If after you update your application to iOS 18 and you find that it is still opted into game mode and you do not want lower-latency audio, lower-latency game controller input, or other characteristics of Game Mode, you can add GCSupportsGameMode=false to your app's Info.plist.
Recommended
See also https://forums.developer.apple.com/forums/thread/739387 w.r.t. LSApplicationCategoryType.
Maybe you added sustained-execution