All fantastic. I can't speak for the A7iii since I've never used one.What about Pany's vfr, stabilization, and 10 bit 4:2:2 capability? Those features are the main reason why I haven't ordered the A7III yet.
I did a lot of research on the Gh5 vs the A7ii and A7iii before ultimately buying the GH5.
With the right lighting, the GH5 is very hard to beat, especially at the price point.
The only weakness IMO the GH5 has is the low light performance due to the micro 4/3 sensor vs the full frame on the Sony.
Even that can be debatable since the performance isn't terrible, but when you put it up against a A7iii you can see a big difference, so it isn't necessarily bad, it's just weaker by comparison.
The stabilization on the GH5 is nuts by the way. With the right technique, I can shoot handheld and get very smooth shots.