Hello darielfromnashville,
If you have a stuck or incorrect unread message number you can try rebuilding Mail to see if that corrects it.
1. In the Mail app on your Mac, select a mailbox in the sidebar.
2. Choose Mailbox > Rebuild.
Rebuild mailboxes in Mail on Mac
If the number is still stuck/incorrect, you can try removing and re-adding the email account in the Mail application.
1. In the Mail app on your Mac, choose Mail > Settings, then click Accounts.
2. Select an account, then click the Remove button
.
Log out of or remove email accounts in Mail on Mac
In Mail, choose Mail > Add Account, select an account type, then enter your account information. Make sure the Mail checkbox is selected for the account.
Add email accounts in Mail on Mac
If the number is still wrong, you'll want to contact Apple to report the issue: Get Support
Cheers!