It would help with a better explanation of your usage scenario
Can Virtual cam or similar take the video output and use that in PowerPoint (PPTx) - sure. But realize OBS is a tool to composite various sources into a video feed, to the typical scenario is a webcam, PPTx, and other content, being merged/manipulated in OBS, then streamed to someplace like FB, YouTube, Twitch, etc, or more recently to a web conf tool like Zoom, Teams, WebEx, etc.
So, your better question might be - what format video input does PowerPoint require/accept, and find corresponding output from OBS. But then what? are you showing off that PPTx slide to someone else? is this in-person/projector style output, or ? Do you plan to record/stream that PowerPoint? if yes, using what?
