Hey there G41_25,
Based on your post it appears you're receiving Mail alerts 10 minutes late with incoming emails. Is that right? Receiving those notifications can be important, so reaching out about this was a great step to take.
Does this seem to affect multiple email accounts?
If so, what happens if you toggle "Play sound for notifications" off and restart your Mac before enabling this again to test?You can do so in System Preferences > Notifications > Mail. Use Notifications on your Mac
Should you continue to run into issues, you can also test the issue in and out of safe mode. Safe mode will clear the system cache, and attempt to repair any directory related issues.
Take a look: Use safe mode to isolate issues with your Mac
Regards.