Using New Outlook on Windows for personal email, calendar, and contact management
I had the same question, and I found something that works well for me:
I go to my email draft (whatever it might be).
At the top right I hit the little options button/the three dots (...)
I go down to Save As...
Save it as an Email Message.
Then I go to where I saved that file (usually on my PC), and then open it over and over again,
This way, I get multiple copies of the draft to open; same subject line, text body, attachments, formatting, links, etc. though it doesn't carry contacts/to/from over.
Hope this helps.