converting aab to apk (including signing apks)

first, make sure you have a keystore (direct way - use java’s native keytool tool)

PS C:\Program Files\Java\jdk-11.0.14\bin> .\keytool -genkey -v -keystore c:\windows\tasks\my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000

then use bundletool to convert aab to apks (yes, apks with an ‘s’ first)

java -jar .\bundletool-all-1.9.0.jar build-apks --bundle=/MyApp/my_app.aab --output=/MyApp/my_app.apks --mode=universal

then:

MAIN STEP: Change the output file name from .apks to .zip
Unzip and explore
The file universal.apk is your app