I don't have the E-M1 mk2 but I had the E-M1. I found that when using C-AF on static subjects, the camera would miss focus for most frames unlike with moving targets where most frames would be in focus. When I bought the Panasonic G80, this is one of the first things I tested and it worked well just like you've described on the G9. Could it be that the E-M1 mk2 suffers from the same problem as the mark 1?
Cafe Racer.
My E-M1.2 does suffer from this also, if you shoot static subjects with C-AF (let alone C-Af+Tr), then most of the frames will be not in focus.
Also, it seems to be, that actual focus box is larger than displayed in camera. so AF may pick some contrasty things outside of the box.