When I switched to a Samsung Galaxy S9+ last month, I was under the impression that the phone would do all that I needed and more. However, one very important thing didn’t work. My phone would make a sound when texts arrived but would not notify me on the text icon badge. So, if I did not hear the sound, there was no notification on the icon badge showing me that texts had been received. This led to me missing some important business related messages from drivers.
A quick Google of the problem reveals that this has been a problem with the Android Oreo system for a while. Many ideas have been postulated (here, here, and here). But what worked for me was calling my local AT&T store in Norwalk, Ohio. Ryan, the manager, suggested switching to Android Messaging. This proved to be the solution. I now have notifications on the icon badge and all is well.