[brazen1]

For UHD processing (a UHD 1:1 source) - Nothing.  My GPU isn't strong enough.  I also don't think any GPU is capable of using 'high' settings at this time.  SD and HD can be used though but you want UHD.
I asked that you list the settings and I would fill in the blanks.  Anyway,

For UHD (2160p) Scaling:
Chroma upscaling - NGU AA MED.
Luma image upscaling - NGU Sharp

Quality:
luma doubling - High
luma quad - let madVr decide (because of title variances)
chroma - let madVR decide (because of title variances)

Activate double/quad - only if any upscale is needed for double and quad (since UHD does not need to be upscaled).
If it did need more scaling for some odd reason:
upscale algo - Jinc AR (for a source that was not quite UHD but higher than HD)
downscale algo - SSIM ID AR LL. (For a source that was higher than UHD and not lower to conform to my UHD display)

Until I upgrade my GPU, I cannot experiment with UHD processing using any of the new artifact removal algo's:  RBA, RRA, RCA, or RRN.  Currently when viewing SD and HD all is well.  When viewing UHD I must turn down Sharpness in my display from 71 to 21 or too much noise is introduced.  Perhaps these algo's would clean that up so I don't have to manually intervene my display settings.  I hate it tbh.  If my AVR was dual output, I could use a dedicated HDMI port for UHD only and the setting would be exclusive, but I don't.  I could get an HDMI splitter but I'm afraid it would degrade quality or introduce more complications than it would cure.  So I live with it for now.  Maybe Samsung will realize the mistake they caused in a firmware update that removed UHD HDR as a separate configurable mode within the same HDMI port.  3D mode is still a separate configurable mode using the same port so why they did away with HDR I don't know.  This is the real cure I await although I may be waiting forever.