Thank you Frajman Tomas for posting about the same issue I am experiencing with the Copy/Paste function in the New Outlook which was what I wrote about when I started the chain of posts. It is different than what the other MS Outlook users having been describing.
I have a template saved in my Drafts section which, in the Classic Outlook, I could paste an exact copy into a new email. As you noticed, Microsoft took that function away.
I used Outlook's Feedback to alert Microsoft of the Copy/Paste issue hoping to get a response. Apparently, they do not read these posts.

When I did that, I received an automated response which was disappointing.