Hey Stanko Kostic! Thank you for the commendation. Unfortunately, I have never published an app for Appstor, but in principle, I think, your actions should be like this:

• First Case: in Xcode, go into the folder that has the same name as your project. In there you’ll see Images.xcassets. Open Images.xcasset and you’ll see yet another folder named AppIcon.appiconset. Double check your app icon here. Than you are good to go with Asset Catalog.
• Second Case: If there are no Icons, then run your project and check the build report. You should see the folder path that describes the location of your project’s final products. Under that, you should see the folder path of your project directory. Navigate to the first path in Finder and look at what’s in there; you’ll see all of the products of your app, including all of the app icons. In this case you should not use Asset Catalog.

Anyways if your app is building and running without Icon/Path related errors, with proper Launcher Icon — you are good to go, as it is.

Hope it helps! Thank you for reading once more!