Hi @Taotronics
The good news is, you can use DexGuard today if you are packaging your app using Android app bundles, but you would be correct in saying that we can do better in how we support App Bundles.
We have work in progress right now for an upcoming DexGuard release that will improve the support we provide for app bundles. Part of this improvement is updating our documentation to reflect better how to work with app bundles. We also want to improve the UX for Espresso testing bundles. Otherwise a lot of our effort is just refactoring to handle the internal model of files in an AAB and how it is different from an APK, including how we handle the Android Manifest.
In summary, over the next month we’ll be finishing up this work and will be in a better position for our support for app bundles. If you, or anyone else reading the thread has specific feedback or use cases they are concerned about, please reach out!
As a side not, we’ll also be adding AAB support to AppSweep, in case you use our service for testing your app. 
Thanks,
Ryan