How do I turn my Android into a USB Webcam?
I finally found a way using USB debugging support on the Android. The steps are quite involved, but here they are: http://www.dev47apps.com/droidcam/connect/

Careful, your phone can overheat when doing this for awhile. Also keep in mind that 4k is not supported, just 1080p. Both on Wifi &amp; on USB the framerate alternates between super fast (>30fps), and super slow (&lt;4fps) in both OBS &amp; iSpy. Not sure why. I think it's the app since native video recording works.

I'm going to do native recording and use a clapping trick to sync audio between an external mic and the internal one from here on out.