I think the following will work, but it requires Zoom to be installed on both devices:
1. Start the Zoom meeting on one of the devices. The iPad should have plenty of power to do this.
2. Use the second device to log into the meeting, launch PowerPoint, and share that screen with the rest of the meeting. When you are done presenting the slideshow, you can stop sharing that screen.
I think I have seen this method used recently. If you know a second Zoom user, it should be easy to set up a Zoom meeting with them to test this method.