Microsoft ToDo not showing badges counts on a Mac

First, make sure Microsoft To Do has full notification permissions by checking System Settings → Notifications → Microsoft To Do, and confirm that “Allow Notifications” and “Badges” are both enabled. You can also try signing out of your Microsoft account in the app and signing back in, or restarting your Mac after re-enabling notifications. If the issue persists, some users have found that deleting the app’s preferences file (com.microsoft.ToDo.plist) or installing the app through the App Store instead of the Microsoft website helps. Hopefully one of these steps gets your badge count working again!

------------------------------------
Don't forget to mark as solution if my answer suits you