For those who don't know, in PowerPoint go to Setup Slide Show on the Slide Show tab and select "Browsed by an individual (window)" and then share that window. Great for Zoom et al.
I use OBS to handle the screen sharing because it is easily to misclick the wrong window that are not for public view. In OBS, it is binded to specific window titles and it is easily to edit out the black bar on the top of the PowerPoint that appeared in Zoom directly (without OBS). I have a few scenes set up this away and quicker to switch than doing it through Zoom itself.