Thanks to @Joe Roxx, @0301chris, and @flamidey for the guidance on capture cards. And fingers crossed that the X-S10 gets full Xwebcam2 support, but given that we don't know when or if that will happen and what the resulting quality will be...I decided to experiment on the cheap ($26 total) with:
Micro HDMI to HDMI Adapter Cable, Wenter 6.5ft/2M Micro HDMI to HDMI Cable (Male to Male) for Gopro Hero and Other Action Camera/Cam with 4K/3D Supported
Video Capture Card, GUERMOK USB 3.0 HD Audio Capture Card, 4K 1080P60 Capture Devices for Gaming Live Streaming Video Recorder, Compatible with Windows Mac OS System YouTube for PS4, Switch, Xbox
So far so good. It's the same level of control (everything set up on the camera), but with a much better image (full frame rate). Wishing I had pulled the trigger on this from day one.