You might want to have a look at a filtering solution such as procmail.
You can have fetchmail collect the mail from your IMAP or POP (or whatever) server and then specify in your
~/.fetchmailrc configuration that it should deliver with
procmail (see the
mda setting in the manual). You would then set up procmail to filter the incoming mail into one or several mail boxes.
I'm just mentioning procmail because that's what I've been using for decades. I'm sure there are other mail filtering software out there.
Example fetchmail configuration:
user "me.there" password "password" is "me.here"
mda "/opt/local/bin/procmail -m $HOME/.procmailrc"
Snippet from my
# [cut several lines]
In your case, you would add a delivery receipt for mail that you've sent yourself. These would go into a separate folder.