Now I'm using Xcode 13.4 but still facing the same issue. I can not install on iOS 14 devices as well as I'm not able to install on iOS 15 devices. I've trusted "Xcode Server OTA Installation" but still facing issue.

Xcode 13.3 is not supported in OS X 10.15.7. Xcode 12.4's App Submission will be close to the App Store in the next 10-12 months. Till then I can use Xcode 12.4