Don't waste time assuming it's just a bug on your end - if it started suddenly two weeks ago, there's a good chance something changed either in the app itself or with your phone's system settings. The usual toggle-on-toggle-off fix doesn't always catch everything, especially if there's a deeper permission issue.
Check your phone's system notification settings separate from the app itself. On iOS, go to Settings > Notifications > BeReal and make sure "Allow Notifications" is on, the sound is enabled, and it's not set to "Deliver Quietly." On Android, it's Settings > Apps > BeReal > Notifications, and you'll want to verify the app has permission to send notifications there too. Sometimes after an update, your phone's settings reset or the app loses permission without you realizing it.
If that doesn't work, try clearing the app's cache (on Android: Settings > Apps > BeReal > Storage > Clear Cache) before reinstalling. Also worth checking if BeReal itself had a server issue or app-wide notification problem around two weeks ago - occasionally the service has hiccups that affect everyone for a bit. If you're still stuck after all that, reach out to their support directly with the exact date it stopped working, since they might be able to see if there's an account-level issue or if you got accidentally muted somehow.