Is there any way to add a second camera?

Yes, if you have a switching board, going into your computer as a source. ATEM mini pro and other such products, I believe, give you that capability

You can add a separate camera, but you can't access them both at once. You can switch between them in a show. I get around this by using my phone and bringing it in as a guest. This allows me to talk to my screen but also have an overhead shot of the work being done at the table (the phone being on an extensible arm clamped to the table). Just be sure to have the phone plugged into power -- streaming on the phone is a battery drain.

you can add as many cams as your device allows and simply select the cams from the audio/video settings and adjust accordingly if you want 2 angles at once.