Mail Notifications

Apple states that this can be done in Apple Mail Preferences: https://support.apple.com/en-ca/guide/mail/cpmlprefgen/mac

New message notifications

Choose the mailbox for which you want notifications to be displayed when messages arrive.

To be displayed, the alert style must be set to Banners or Alerts for Mail in Notifications preferences. To open Notifications preferences, choose Apple menu > System Preferences, then click Notifications.

However this may still only be for one email account.

Otherwise, a workaround could be done by setting up Rules in Apple Mail for each of your email accounts....

1. Open Preferences
2. Click on the Rules tab
3. Click on New Rule
4. Enter a description
5. Under IF ALL of the following actions--> Select Account, then choose the email account
6. Under IF IF ALL of the following actions --> Select Every Message
7. Under Perform the following actions --> Play Sound - and choose your sound. (There may be ways to get different sounds added here too. Might need to look that up as I do have different sounds listed here).
8. Under Perform the following actions --> Send Notification
9. Click OK
10. Click Don't Apply when prompted to apple to all messages.
11. Then send a test email to that account to see if it works.
12. If it works, set this up for every email account that you want notifications for.

You may need to make a change to the existing email notification setup in Mail Preferences/General in order for this to work well.

Hope this helps.

Adam