I have OBS installed, but even if I started the virtual camera, I could not use it because the option does not appear in Google Chrome's camera settings. To be precise, in the general settings of Chrome, I can set like the following:
Screen Shot 2022-07-08 at 13.46.46.png
However, on the actual web page, it was automatically changed to FaceTime HD Camera and could not be freely changed here.
Screen Shot 2022-07-08 at 13.47.00.png
Incidentally, Google Meet allowed me to choose the virtual camera.
I have looked for other ways to flip the camera, but unfortunately have not found any.
I have attached the project file above so you can see if the problem does not occur in your environment.