None of the search works in Big Sur Mail.app
To me Big Sur Mail.app is next to useless as none of the search, nor smart mailbox works at all.
I upgraded then immediately noticed that none of my smart mailbox worked, they displayed a correct (?) number of unread message, but clicking on them, just makes the number disappear, and show no message at all, like if it were empty.
Then I tried searches, I took the eMail address of a colleague and it returned 2 results, after a long "Searching…" message occurred.
I rebuilt my spotlight index, then deleted all envelope files, then rebuild the database. No dice.
I even deleted the whole /Library/Mail folder, and after all my iMap mails were downloaded, still same issue.
I'm using a Google Gsuite email imap account, and an iCloud one, same issue