i can give you the one i use in game HDR with latest firmware.
lum 50
contrast 38 , not above or you overshoot the 50% white value
saturation 30
sharpness 0 or 1
localdimming High
dynamic contrast low.
ST2084 -1 (for the same reason above , to keep 50% white correct)
shadow +1
Game Motion plus on , game contrast enhancer 5.
HGIG off , why ? because unless you find a game that uses it correctly, it simply dimmer the max nit to a category2 , so 1000nits max. and i saw burned white while i have no problem when off.
on the PS4 you have also to tune the HDR in PS4 setting in order to tell the PS4 what max nit you have, with the help of their checkerboard. but you must do it AFTER entering the TV settings. moreover , thanks to "clever" samsung gui , the HDR setting on the PS4 is only available if you are already in a HDR game / film.
For SDR, it is easier , it depends on you light env , in dim env you keep saturation to 25. and if you go high in luminosity , you must couterbalance saturation to 18 to 16.
cf my published settings above.
and to remember the contrast in HDR game mode will be always worse that the HDR cinema/filmmaker . so you have to choose either latency or max quality HDR rendering.