Chroma-only denoise destroys color details

Hi, I started to ease-off my denoising strength and often omit the luminance denoising at all. So I tried the chroma-only preset in denoise (profiled), but that has a major side effect: It smooths color details in a fairly extreme way, as I wrote here:

You can see that the flowers look completely washed out if chroma-only preset is used. It seems to happen regardless of the image and the type of camera used (i.e. independent of the profiles).
If I use the default denoise (profiled) using wavelets mode, then some sharp edges have shape-related artifacts (straight lines are no longer straight and edges are often very harsh (compared to non-local mode, not this Curaprox sign example tho)

astrophoto denoise in chroma-only is too weak even at 1000% and i can’t get contrast-equalizer chroma-only to be optimally strong either. What other alternatives are there?

What kinda helps is changes in demosaicing, but only very slightly:

Very noisy image, without any denoising; with default settings of denoise (profiled); with the wavelets: chroma only preset; with my custom preset.

Switching betwed RCD and LMMSE:

With contrast equalizer added to the mix (LMMSE + denoise (profiled) with my preset, then same with contrast equalizer, and finally only LMMSE + contrast equalizer):

And the XMP:
2024-09-18-18-53-01-DSC_0272_12.NEF.xmp (7.3 KB)

And this is just LMMSE + surface blur with defaults, but blending mode set to chromaticity:

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Ohhhh I finally know why chroma-only smooth colors so much… it’s set to strength=1.200 by default and dropping it to 0.500 helps a lot:

The chroma noise seems quite minimal even at 0.500 compared to other methods.

To my eyes, this seems to be the best of them all. LLMSE seems to make noise a bit more noticeable compared to RCD, I’m not sure.

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Be sure also to tweak the protect shadows slider…this one I think is also a key to getting or fine tuning the impact of the module…

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The optimal strength of chroma-only seems to be dependent on the ISO, like for 100 I only need like 0.100, but for 900 I need 0.500… I guess it depends and I’ll have to check for each image. I mean, the default wavelets do good enough job, so I think it’s not that big of a problem

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Heh. This is nind-denoise, with composite, the first instance with chroma blending at 100%, the second with normal blending at about 40% and 60%:

Overall, we went from this to that (end result, with contrast enhancement etc):

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