I'm about to release an app update with a new app icon. I updated to Xcode 13 + iOS 15, and no matter what I try, the iPad keeps showing my previous version of the app icon.
iOS app icon not updating with Xcode 13.0 / iPad OS 15.0
Did you remove the app and reload again, not just do an update ?
If so, it may happen that some cache takes time (several days) to clear.