Apple Mail - Flagged message count is wrong and it multiplies with each mailbox rebuild!

On my Mac Studio Macmail, flagged message count is off and I wanted to fix it by following the methods described in the community in ascending order of involvement:

1. Synchronize accounts
2. Disabling and re-enabling accounts from Mail > Settings > Accounts
3. Rebuild mailbox
4. Exit Mail, Go to Users/mymacname/Library / Mail / V# / MailData and delete all files named "Envelope Index"

1-3 did not do the trick. Many say option 4 works but in my case, each time I perform this, flag count multiplies. The flag count was off to begin with, but having performed this step twice, now the total flag count is 3x the original wrong flag count.

Should I take more drastic action and delete the entire contents of library mail folder? Either that or are there more files in MailData that I should delete together with "Envelope Index" files?

Any help greatly appreciated.

All my mail accounts are IMAP and while I have two inactive accounts, they are also IMAP (GMail and prev. work). Nothing is stored on my Mac.

Mac Studio

Sonoma 14.3.1