No matter what I do, I can't get my notifications to work. Even when I try to choose them, I get no sound. My volume is set as high as it will go, and nothing is set on mute. Any help would be greatly appreciated.
Do you have any lock screen apps? Do you have any themes running?
To wipe the cache partition, which may help:
Finally, try the help items in this article: https://thedroidguy.com/how-to-fix-samsung-galaxy-s9-app-has-no-sound-notification-1096942
If they work for you, let us know which one helped here.