I have a panasonic GX9 and it is a great little camera. Auto-focus, size of lenses is great, video works good, in the right condition iso is good.
I own 7.5mm f2, 15mm f1.7, 42,5mm f1.7. The all lot fit in a tiny bag.
In picture the GX9 is not that much bigger that the A7iii but actually in hand it feel a lot smaller.
Sure the sensor can make the next leap forward that would be great. But i would never buy something like a G9 it is too bulky and way too much money for that system...
Now I have a sony A7iii I need to sell all my panasonic stuff but I do like it more that it is worth just yet.