If you see the "Your device is incompatible with this version" notification on Google Play GWENT page, your Android device is not supported.
If you cannot update/install GWENT go through the steps below:
1. Make sure that you have GWENT installed from Play Store.
2. Uninstall the GWENT app.
3. Clear cache and data of GWENT:
Note: Clear Data will not lead to progress loss in GWENT.
4. Clear cache and data of Google Play Services & Store in the device's Settings app. Refer to the steps 2 & 3 here: https://support.google.com/googleplay/answer/9037938?hl=en
5. Only after the above steps are fully performed reinstall the GWENT app.