LG Ultrafine 5k Monitor camera not working with FaceTime and my Mac Studio

When I bring up FaceTime there is no option for camera input in the Video menu other than "Automatic Camera Selection". A video preview does, however, briefly appear for a second or two from the Ultrafine's camera, but then it flickers out, comes back, flickers out, etc. If I try to make a call like this the person on the other end might see me for a moment, but then there's an error message about the connection being unstable.

"LG Ultrafine Display Audio" does appear, however, as Microphone and Output options.