many duplicates of a few random emails in Apple Mail while using macOS Monterey

I posted a problem a few months ago with an occasional email that became duplicated many times on home and office macs, and online using iCloud email in Safari. It really really slowed down Apple Mail on Mac. I was advised to delete duplicate emails and remove iCloud account from Mac. This resolved the problem but it recurred last month and I repeated the above. Today it recurred again; at the bottom of this post, I list number of duplicates this afternoon, and related notes. So I removed the iCloud account from my Mac (again), and repeated the above and finally duplicates seem to be gone. One curious observation is that the duplicated emails were first from USAA (an insurance/investment company) and more recently from TIAA (investment company). The emails are pretty nondescript like "You have a new document available". The duplication occurs in older emails received 1 week to a few months earlier.

As noted in previous post, reinstalling macOS didn't resolve issue.

Here's a log from today:

TIAA email duplicated many times even with Apple Mail app not running on macs or iphone? Number refers to duplicate count in iCloud web browser Mail.

    1:37 pm     32

1:39 pm     50

1:44 pm     83   

move to trash and empty trash

1:46 pm     25 and 13 (listed duplicates twice so 38 total)

move to trash and empty trash

1:54 pm     6

2:05 pm     36  (and 2:11 pm, 2:53 pm)

move to trash and empty trash; open Mail app on mac

3:04 pm     69

3:06 pm     77

3:08 pm     86

3:27 pm     82

remove iCloud internet acct. on mac; move duplicates to trash and empty trash

3:30 pm     15 (which were then deleted)

This warning appeared multiple times in Apple Mail on Mac Pro running macOS 12.6.1

The message “You Have a New Document Available” could not be moved to the mailbox “iCloud”

The IMAP command “APPEND” (to INBOX) failed with server error: Unexpected exception (took 3522 ms).