Played around with EQ and yeah, and found that is indeed the upper region that irritates me; the spike at that 12kHz point is definitely a huge factor.
Came up with a setting that I find pretty good (for me). Welcome to try it and play around with it if you want.
Preamp: -4 dB
Filter 1: ON Pk Fc 85 Hz Gain -1.5 dB Q 1
Filter 2: ON PK Fc 1000 Hz Gain -0.6 dB Q 3
Filter 3: ON PK Fc 2900 Hz Gain -1.1 dB Q 3
Filter 4: ON PK Fc 4300 Hz Gain 3.7 dB Q 4
Filter 5: ON PK Fc 5850 Hz Gain -1.2 dB Q 4
Filter 6: ON PK Fc 7000 Hz Gain 1.1 dB Q 4
Filter 7: ON PK Fc 8000 Hz Gain -2 dB Q 4
Filter 8: ON PK Fc 10000 Hz Gain 3.5 dB Q 1.5
Filter 9: ON PK Fc 12000 Hz Gain -4 dB Q 2
Filter 10: ON PK Fc 13000 Hz Gain -1 dB Q 3
Filter 11: ON HSC Fc 15000 Hz Gain -2.8 dB Q 0.71
Filter 12: ON PK Fc 15000 Hz Gain 2.2 dB Q 3
Filter 1 and 9 & 10 are the ones I will likely adjust every now and then. The 12kHz spike seems deliberate to try and balance out the hefty low-end of the Radiance. You could increase Filter 1 to 3dB for better balance I suppose, but I like the bass on the Radiance as is even though it can be a bit overbearing on certain tracks (not bleeding into the lower mids or anything, but just a tad too loud for stuff like Jazz).
People may also want to disable Filters 11 and 12 if they aren’t sensitive to frequencies above the 15khz if they like the shimmer on the Radiance as is.
Happy with how these are now.