"Sign in with Apple" on iOS

Hello,

I have a JS website that uses "Sign in with Apple" with AppleID.auth.signIn :

1. It redirects to appleid.apple.com
2. It redirects to my backend with a form POST
3. Then I redirect the user to my frontend

I bundled my website as a webview in an app for iOS. When using the functionality on iOS :

1. A faceId popup appears over my app
2. The user is redirected to appleid.apple.com
3. A second faceId popup appears
4. It redirects to my backend with a form POST
5. it gets redirected to my frontend in an embeded Safari. When closing the embeded browser, the user is not connected on my app

I would like my user to be redirected to my app instead of staying in the embeded browser.
I would like to eliminate the double faceId popups

• The functionality works in the web (Safari desktop and mobile), as a PWA, and on Android. So I think I have properly configured the Domains and Redirect URLs in my Sign in with Apple service.
• When I click on a link that points to my website from Safari, it opens my iOS app. So I think I have properly configured the associated domains.
• When testing the functionality from an iPhone emulator in XCode, it works (but uses a simple appleId/password form instead of faceId)

I could not find an answer on the forums that solved my problem. I can provide code and screen captures.

Thank you