Emmm 4k, I have no idea.
I know that panasonic makes a bunch of cheap 4K cameras like the g85, GX85 and the G7 that you mentioned. Why is it so important for you to have 4K ?
it takes longer to edit videos with 4K, It overheats the camera, Eating battery like crazy..
i would stick to 1080 as a beginner and then in the future i'd buy a good 4K camera, When i'll have more money to buy better equipment to process 4K..

If you still want 4K, I guess your only option is G7 or GX85 by Panasonic..