I'd check out the tutorial here, with information about packaging aab and testing:
Also, if you're using the default FlashDevelop scripts for installing (which it sounds like you are), those are probably using the older "adb" commands for an apk instead of the newer "bundletool"-based commands that aab->apks needs for testing locally.
I'm not sure if my setup is similar to yours, but I would check your PackageApp.bat file in your project folder, and scroll down to the :android-package section. If you see a line like this:
adb -d install -r "%OUTPUT%"
you can try replacing it with this:
call adt -installApp -platform android -package "%OUTPUT%"
I'm not entirely sure if that will work or not, but from the AIR SDK Release Notes it looks like the latest adt -installApp uses the bundletool commands behind the scenes. If that doesn't work, you may have to dive deeper into the "Testing" section at the link above where it mentions using bundletool with build-apks / install-apks commands.