Following the update to Android 8 in 2018 the app notifications stopped working. Although this is a known problem Samsung have not yet issued a fix.

To oversome the missing app notification badges I installed Nova Launcher some time ago. This at least made the notifications visible but I still never get any app notification sounds although there are occasional buzzing noises which I assumed are vibrations, even though this was not specified in any app settings.

Any suggestions on how to get sound notiifications again?