Hello all! I know there's been some discussion around getting app notifications to display with DUDUOS. I was looking for something that worked with Whatsapp, Google Voice, and Messenger, since without popups I wouldn't see incoming messages until opening that specific app.
I've been testing Floatify over the last month for this purpose. Floatify allows for control of any app's notifications. It's very configurable - you can choose the duration of the popup, modify its location/size/theme, respond to messages within the popup (without bringing the app to the foreground), or open an app from the popup. It also supports gestures.
This has been exactly what I needed. Floatify is no longer in the Play Store, but you can find it on Softonic or Uptodown. Hope this helps!