Nice! I built something along these lines but far more janky. My setup is a clamp-mount mic boom arm and an L-shaped bracket, along with a mic-to-1/4" adapter. Boom clamps to the monitor arm, reaches over the monitor, then the short end of the L is attached to the arm via the adapter. My webcam has a 1/4" screw built in, so that attaches to the long side of the L.

I've been using it for years, works great to get the camera down for calls and back up out of the way when not needed. Only problem is that it's not super stable so I have a small spirit level insert glued to the top of the camera to make adjustments easier.

Edit: somewhat recent photo of my setup, including the webcam: https://imgur.com/a/ip3ff4F

External USB C monitors are getting cheap enough to make a dedicated 2-way mirror teleprompter style webcam setup reasonable.

https://www.youtube.com/watch?v=2AecAXinars