I think your call Clipboard calls are getting plain text out of Word ... but Outlook will need HTML.

This (very old) thread has the same question. Solution there uses VB to save/convert the doc to HTML, then send a copy of that HTML to Outlook. I expect this is the route you will need to go:

https://www.experts-exchange.com/questions/23606380/Copy-Word-Doc-to-Body-of-Email.html

Ah, same one here, also:
How to send a Word document as body of an email with VBA