Sorry but I don't read or care about all the measurement done by various internet experts. I only trust my own results or those that I know personally. The D850 image quality, when converted with the right RAW converter is superior.
the D850 buffer is quite good with the XQD, I can shoot about 4 seconds before it slows down, if that is not enough one should start questioning their skills. The frame rate itself is not fast enough for some subjects but neither is the D500. For that you need the D5.
Again, IMO if you can afford it, the D850 it is a no brainier. In fact for many situations I prefer the D850 over my D5. The grip cost is nothing in the overall system and I like that it uses the same battery as my D5, I don't have to carry two kinds of batteries and chargers. The D850 is the jewel of the Nikon brand.