All the shortcomings of micro 4/3 stem from a small sensor with large noise. As well as the advantages in lens weight. But Panasonic's wide zoom autofocus lenses themselves are not of very high quality and do not work out the declared resource, and are also extremely weak in auto focus precisely because of the poor dynamic range of the sensor and partly of the optics themselves.

Once upon a time, cameras weighed significantly less, but now all the weight advantages are almost lost in micro 4/3, especially in the GH series. And the price has tripled in 14 years...

The focusing system on the G9 is good, but not stellar. Moving subjects are an issue, with a keeper rate that's a bit low. Birds in flight, in particular, are painful to photograph.
I moved to the Sony A1 a while ago, and it's a different world in these scenarios. I love the G9, it's an awesome camera, but it can't compare in the focus department.

Who da heck writes those generic uninformative articles?
The lumix G9 has one of the fastest if not the fastest autofocus and also very precise autofocus  in the M43 system. Any photographers using it will tell you the same.
The only downside is AF while shooting video, but the G9 was made for photography not video.