Thank you for the details, I definitely understand your frustration.
It sounds like there is a bug, notifications are either to notify you of a blocked item (reactive), once every release to notify you of any changes (once or twice a month), and once a month to give you your protection stats.
It sounds like you are getting the protection stats notification multiple times a day and on different tabs; this is absolutely unintentional and indeed very aggravating.

I know it's a long shot, but if there is anyway you could share your logs with us at support.malwarebytes.com, we can stamp out that bug.

I understand you're not interested but just reference for anyone else, all notifications in Browser Guard can be controlled on the Settings page. Sounds like we need to do better in exposing that.
The instructions to disable the notifications are here https://help.malwarebytes.com/hc/en-us/articles/31589256837403-Customize-Browser-Guard-from-the-Settings-screen