Google Pixel video camera app -- NOT FV-5

I need a way to record video on my Google Pixel with an external microphone. I don't think it's possible using the built-in video camera. Almost everyone else with this problem suggests using Camera FV-5, but I've had no end of trouble with that app. It's buggy. It does weird things with focus and exposure, seemingly unpredictably. Is there another app or method?