Although I haven't bought the RX10IV, I did go to a dealer and shot off about 30 Raw exposures both in and outdoors. I found the images very noisy at 400iso and above. Even using noise reduction which took a lot of fiddling, the shots never looked that great. It has a great lens and feels good in my hands but the noise issue really put me off.
Too bad since I was ready to buy it.
Brian