Here is color propagation method in RT and nothing else. Settings were selected to eliminate blue tree fringing.
_DSF9414.RAF.pp3 (11.7 KB)
It is sublime for the blue skies, but awful for the cyan clouds and building highlights. View those at 100%. I don’t know if RT has a sat/luma curve that allows you to just desaturate the cyan out of those clouds? If not, then I would wish to export two different versions, and combine them together with masks.
Aurelien’s demonstration looks to strike a balance between the two. Nicer blending, cloud (highlight) colour, and no blue tree fringing, at the expense of some blue sky.