Refer:
https://facebook.github.io/react-native/docs/signed-apk-android.html

create your own key store file

https://errong.win/generate-keystore/

modifications

error INSTALL_FAILED_UPDATE_INCOMPATIBLE

https://errong.win/react-native-run-android-variant-release/

java.lang.NullPointerException (no error message)

When I set below values to true, I encountered NullPointerException.
so my reset them to false again.

+ def enableSeparateBuildPerCPUArchitecture = true
+ universalApk true  // If true, also generate a universal APK
+ def enableProguardInReleaseBuilds = true

error can't delete/read lint-results-release-fatal.html

kill all java.exe via task manager