Hello KANGA472,
Thanks for posting in the Apple Support Communities. We're happy to look into this with you.
We found article, Manage notifications from Calendar on Mac - Apple Support, that provides information on how to adjust your notifications for a specific calendar on your Mac.
Manage notifications per calendar
1. In the Calendar app
on your Mac, Control-click the name of the calendar in the calendar list, then choose Get Info.
2. If you don’t see the calendar list on the left, choose View > Show Calendar List.
3. Select or deselect “Ignore alerts,” then click OK.
Be sure to review the full article for additional recommendations on your settings and how to adjust them.
Best regards.