Currently Expo uses https://developer.apple.com/documentation/authenticationservices/aswebauthenticationsession/init(url:callbackurlscheme:completionhandler:) internally when calling openAuthSessionAsync. This signature is deprecated and only supports custom scheme callback URLs. https://developer.apple.com/documentation/authenticationservices/aswebauthenticationsession/init(url:callback:completionhandler:) instead supports both custom schemes and universal links. It's only available from iOS 17.4, but it could be used conditionally.