Guys, please help I'm just a beginner and currently making my first app and I need this in that. I haven't yet started UIKit and an building this app in SwiftUI so preferably please give the answer for swiftui.

Hi, this is the first time I am experiencing a major iOS release since I started developing, so I have some questions. My app doesn't work perfectly with iOS 15 beta how do I fix it? When I make my app from Xcode 13 after the final release will my app still run on iOS 14? As currently my app doesn't run on iOS 13 or 12 and I don't know why. Thanks in advance