Can I restore deleted email account on Macmail?

Good chance you have overridden the mail account folder
Which means the old emails are gone.
You could be lucky and outlook might have made another folder.

Each user account on your Mac has a Mail directory in their Library folder-that's ~/Library/Mail , or /Users/[NAME]/Library/Mail . This is where the Mail app stores its data for each user.
To see it, open Finder, click "Go" in the menu bar, and choose "Go to Folder." Type ~/Library into the box and press Return
From Here

Do you have time machine in use
You may be able to get them back with time machine

Is the account imap or pop?
If imap I would check the account’s sync settings to see if it is set to only download recent emails rather than all emails.

Thanks for reaching out guys. Still struggling.
Mail folder in library is gone. Time Machine only runs back 24hrs. Can not seem to get anything older.
The old deleted account was imap. The new is exchange.
Does that help? Thanks again.

If the account was imap then those emails may still be on the webmail version of the account - if not then they’re gone for good.
I would still double-check to see if the account is now set to only download the last x number of days rather than all mail.