Sorry, I'm not using C4D. I'm working with .OBJ and .FBX files. I'm sorry but I can't figure out how to generate a log file from the standalone version.
If you can see the images here, one shows an error I get when trying to open an existing file (.ORBX).
The other one shows me trying the metal ...

I'm having this problem too. I've managed to get a couple of things to render, but most of the time I get a grey or white render window. Using the free version from the Mac App Store. Mac OS Big Sur 11.2.3, MacBook Pro 2017 15", Radeon Pro 555 graphics.