Mail searches used to be lightning fast and results appeared as I typed. For the last few months, they're been super slow (macOS 11.5.2, rMBP 2015). I one account with less than 2GB of mail.
I've tried all the usual tricks, deleting and re-adding my account,
sudo mdutil -E / to rebuild Spotlight indexes, and deleting
Envelope Index. Didn't help.
Spotlight outside Mail operates normally.
Anyone else seeing this?