We do a lot of small livestream gigs and did develop a graphic solution for adding powerpoint and graphics into a videoswitcher. We call it SuperSource. You find it here: supersource.live
I was hoping someone in this forum could check it out. We have not had any time to make any instructions videos, but some part of the application should be straighforward.
We use a elgato camlink card to grab the powerpoint/keynote and add this as a background into Atem Mini/Pro.
Hope some of the members have time to test