Find which specific app is doing the notifying, and go into its settings and turn off notifications.

and set time for it to begin and end. The notifications are probably being sent by the galaxy store. You can open the galaxy store app and go into settings. You can't turn off notifications for the galaxy store, but you can silence them. Hope this helps.

It took a while but I found it and chose "silence". Hopefully this will stop. I was worried about shutting everything else off.

Glad to help.