Can't advance PowerPoint Slides from new "My Screen" tab

Welcome to the Zoom Community, @BradWallace.

My experience is that the keyboard will only control PowerPoint when PowerPoint has the computer’s “focus” – that is, positioned such that the keystrokes will go directly into the application. This has always been the case, and is one of the reasons that the default behavior when screen sharing is to only present the menu bar and the small green and red bar beneath it. 

Are you talking about projection screens being driven off of a PC? I’ve seen Dual Monitor mode used successfully to selectively drive the video to projectors or LED walls. There are many possible ways to make it work, and many more ways people try that don’t work. I’d recommend having your IT department with directly with Zoom Support to work out a configuration that works at your institution. 

I am a person tasked with solving this issue for faculty/staff. This is for any scenario where someone would have a hybrid meeting and use a PC that was sent to classroom screens. There was no issue with this preferred setup before the update. You could advance slides while allowing in room attendees to also see the gallery. Now you can't. I'm hoping someone from Zoom has a solution or a work around.