I have never received receieved notifications through the usual notifications at the top of the screen, does the app not do that or is it my phone? I have to open Jerboa to see that I got either a reply or a message.
I use the F-Droid version of Jerboa on GrapheneOS 13.
I don’t think Jerboa supports ‘native notifications’ which means it relies on other services (such as Google Play Services) in order to push notifications to your phone. Some applications (such as Fairmail, F-Droid) don’t rely on Google’s services and use the OS’s native notification abilities.