Camera Live works with non-canon models as well, there is at least partial support for some Fuji and nikon in the alpha releases and it looks like the maintaine

Camera Live works with non-canon models as well, there is at least partial support for some Fuji and nikon in the alpha releases and it looks like the maintainer intends to increase support even further. The heavy lifting appears to be done in libgphoto2 which supports a ton of different models. In terms of “why don’t you just use ____”, I have scoured the web for any way to use a Nikon as a webcam on macOS (over usb, so without dropping $120 on a camlink which is sold out everywhere now anyway), and the only other thing that exists is an app called ecamm live which costs $20/month forever. For windows and even Linux there are other more affordable or open source options.