Open the link below and follow step 1 to step 5.3
https://documentation.onesignal.com/docs/huawei-sdk-setup
Note step 4.3:
Make sure to provide the SHA256 for both debug and release keystore in your huawei config (step 4.5) so that the push will work if you plan to test the push using the command "react-native run-android".
The debug keystore is located under android/app.
If you want to know how to check the SHA256 inside the keystore just refer to the guide below.
https://www.aboutonline.info/2020/12/get-android-keystore-information-from.html
Hope this helps