Edge lighting fix by Zunderstruck is the only solution i know of. Edge lighting off screen is broken on galaxies because of overlay and notification prioritizing issues within the os code. Unless you really dont want to use the app, grant it permissions in the notifications section of the settings app, as well as in the Manage Notifcations within edge lighting. Also to make it work properly, in the By Text portion of the edge lighting Custom Color selection, write out the main title of the google rcs messages notifications and assign it a color. Thats how you make it work, not just by having it in the By App selector. Finally go into Apps>google message>notifcations and set all the notification style sub-categories you want to Sound And Pop-Up.
... View more