Is it possible to upload an application build to the App Store via Xcode?

Yes, it is possible to upload an app build to the App Store via Xcode. The steps are as follows:

1. In Xcode, select the project scheme and configure the signing profile (Provisioning Profile).
2. Archive the app through Product → Archive.
3. In the Organizer window that opens, select the created archive and click "Distribute App".
4. Choose the option to upload to App Store Connect.
5. Follow the instructions to upload and submit the app for review.

Thus, Xcode provides an integrated tool for preparing and submitting the app to the App Store.