Android Studio now fails Generate Signed APK with "The project is using an unsupported version of Gradle."

Android Studio has started failing to Generate Signed APK.

In November 2019, I found and described how it used to be possible to get it to work if you used the right version, etc., as I detailed here: https://forum.openframeworks.cc/t/notes-on-steps-i-took-to-successfully-get-a-64-bit-apk-published-to-the-google-app-store/33722

But now even that configuration doesn't allow Generate Signed APK.

APKs can successfully still be built even using the latest Android Studio versions, but the Generate Signed APK fails, and it is not clear what to do in order to be able to codesign the APKs for submission to Android Studio. I gather it is possible to manually sign them, but I find the Android documentation on the subject to be extremely confusing (and trying to push people to accept their new bundle scheme and use Android Studio).

So I think OF at the very least needs some clear documentation on how to codesign APKs for the Play Store, I'm trying to figure it out myself, and would be happy to write it up, but I could use some help understanding what exactly needs to be done to do this.

UPDATE: Through trial and error, I found that I AM still able to codesign if I use Android Studio 2.3.2 or Android Studio 3.1, but not Android Studio 3.5.1 (due to the Gradle issue mentioned here).

Review the linked forum notes and the reported Android Studio versions, especially 2.3.2, 3.1, and 3.5.1. Document a current, reproducible process for code-signing APKs for Play Store submission, including the known version limitations and what to do when Generate Signed APK fails.