Webex has a "presenter" view for Powerpoint but you should share it as a file instead of Screen or App. When you share it as a file, you will lose any slide transitions but you have the ability to click on a "4 square" icon on the annotate tool on the left that will open your thumbnails. If you have speaker notes, you can click on the circle with 3 dots in the bottom right of your screen and click on "PPT Notes" to view your speaker notes. The attendees only see the active slide but you now have thumbnails and speaker notes available to view.
