In order to solve the blackscreen issue, please try following the troubleshooting steps below:
- Make sure that no external application is interfering with the game.
- Ensure that your game is downloaded directly from the Apple App Store and updated to the latest version.
- Try launching the game first using Wi-Fi connection and then switch to mobile data transfer.
- Reinstall the game a few times.
IMPORTANT: Before reinstalling the game, please make sure that your Witcher account is connected to your Google or Apple account. If you haven't linked your accounts before, you won't be able to log into the profile you used before the reinstallation.