GoPro now makes it possible to use an existing Hero8 Black camera as a webcam on the Mac.
For this purpose, a firmware update is required, which you can find here. The corresponding software for the Mac (and also for Windows, currently in beta phase) can be found under this download link.
Basically you only have to connect the camera and install the software. A more detailed manual (with some outdated information about the software versions) can be found here.
If you don’t have a Hero8 yet, but want to buy one because of this handy function extension, have a look here on Amazon.