How to test Android In App Billings--I've tried "everything" but no luck

I am trying to get a list of Android In App Billings (IAB) in my app--subscriptions specifically. While debugging on device (NOT EMULATOR) When it makes the call to get the products I get this error error occurred while loading products: Error: IAP not prepared. Check if Google Play service is available. Here are the things that I've done:

1. The apk is uploaded to the Google Play Console as an alpha release.
2. Hours (days!) have passed and the release is available (I can see it in Play Store).
3. I added the in app purchases in the Google Play Console.
4. I added a gmail account as a tester in the Google Play Console in both the general settings area and the list of testers for a release.
5. I installed the apk that has the same version number AND version name as the apk that is in alpha in Play Store
6. I am using a real device (not an emulator)
7. I am signed in as the tester email account.
8. My AndroidManifest.xml has the BILLING property set

It should be noted that I am using react-native and this package for in app billing https://github.com/dooboolab/react-native-iap although I think the issue here is I have missed one of the general steps necessary to set up in app billings for Android. Any ideas or guidance would be appreciated--I've been fighting this for days now!

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