Big Sur Mail Issues: VIPs gone. Flags: half gone. Search not working.

To summarize:

> Using Big Sur 11.6

> Mail search gets no results.

> VIPs in mail are gone (toggling a VIP status in any given messages changes nothing)

> Flagged messages show only the last three or so for each flag, but only four of six flags show

I've restarted the computer and the mail app multiple times. No change to mail.

What is going on with Mail?