Notifications MacOS Big Sur

We switched all of our staff over to Rainbow this year, and the biggest complaint is they aren't receiving any of the notification sounds when they receive a message.  I've double-checked all the settings in Rainbow and it is turned on and the volume is turned all the way up.  It would help if we could get a banner to stay on the screen.  Can we get Rainbow added to the macOS Notifications Center so we can customize notifications more?