Hi Blanc,
I had this exact issue today and actually made the same smart folder.
I found this older topic - OCR on PDF files attached to e-mails? - #63 by BLUEFROG
I then got the script there from BlueFrog, and ran it on all the emails in the smart group. Took about 15 minutes to get through it all but worked great.
I’m thinking about loading my outlook into Mail just to get the “Add attachments and Emails” script as it’s so useful. If you find an alternative I’d be very interested.