Mailboxes in 'On My Mac' in Ventura

I have over 300 mailboxes/folders in On My Mac in Apple’s Mail.

Prior to Ventura, I could search for something like ‘Microsoft’ and the search would show Folders, Mailboxes and emails with ‘Microsoft’ somewhere in the email or Mailbox.

Now it seems to find only emails and attachments. It’s getting harder to remember where the Mailboxes might be, but I can’t find anything that will show Mailboxes in On My Mac in the search within Ventura. Is there a settings file?

Can you help?

Brad Smith