Just my opinion: I think the Apple Studio displays are not good enough for judging color from a mastering point of view. It's widely known that even Apple does not use their own displays for making their commercials, TV shows, and presentations (though I'm sure many of their computer systems use them).
For judging color from Resolve, you need a display connected to a Blackmagic display adapter like an UltraStudio, and then the display has to be calibrated with an external probe and software like Calman or Light Illusion.
Read these two articles by Light Illusion's Steve Shaw:
Why Calibrate?http://www.lightillusion.com/why_calibrate.htmlWhy Master on a Calibrated Display?https://www.lightillusion.com/grading_displays.htmlThe point is that whatever flaws are built into a computer display will affect your work: if it's too blue, you'll go in the opposite direction and make it too warm; if it's too dark, you'll overcompensate and make it too bright.
Also, read page 2890 of the Resolve 20 manual, "Limitations When Grading With the Viewer on a Computer Display." This explains why it's unwise to try to use a computer display for final color correction, even a computer monitor as costly as Apple's. The same problem also exists with the "Clean Feed" output, since it's not color managed.