No, Anna, I don't think you can copy/paste from Office in to PD - or most video editors I should think.
Anna; I have been making educational videos for many years.
I find using png files is not at all a tideous workflow. I have some folders where I have stored png assets over the
years and I can quickly find and import them.
I wonder; are your videos for students? Collegues?
Or do you have pehaps a channel you wish to promote as an "edu-channel"?
Have you had a look at Office Mix?
You could then use PowerPoint.
Cheers
Just something.
https://www.petitpoisvideo.com