P: Denoise on DNG from Ricoh GR-III x is missing Luminance Denoise-

I allready tried DxO pure RAW. Not working with the GR IV.

Same as the GRIII, Ricoh is baking in DNG noise reduction for any image shot over ISO200, and you can't turn the feature off.

Adobe claims Ricoh would have to stop using their baked-in RAW noise reduction for Lightroom's AI NR plugin to work, and Ricoh isn't going to do that (well, they certainly never bothered with the GRIII, so I doubt anything would change with the IV).

Some other advanced NR plugins with work with the GRIV (reportedly... I haven't tested personally), like DxO's PureRaw.

Given's it's been years of Adobe being unable to work around Ricoh's raw NR system, I wouldn't expect it to change any time soon. 

It's best not to hope that Adobe and Ricoh will solve this problem together, but to find suitable replacement products, whether software or cameras. I changed software because I love GR too much.

The option for AI noise reduction seems to do nothing to Ricoh GR IV DNG-files. After processing noise is is still visible.  Don't have the same issue with Sony files. Looks like a bug.

Any sugestion what causes it and what could be a solution? 

The workaround with DNG lossless conversion seems to remove too much detail and does not work as expected, unlike how denoise is supposed to perform.

I'm left wonderring if the new GRIV rectifies this?

您测试的结果如何呢？

Here's a potential workaround:

I downloaded one of the sample files provided above:
https://rebafoto.ch/dpr/RI002451.dng

If I select that DNG and do Library > Convert Photo To DNG with the option Use Lossy Compression, Denoise works well with that new DNG. This aligns with Adobe employee Rikk Flohr's implication that the camera was generating DNGs that didn't fully conform with the DNG standard. Converting to lossy DNG is writing a brand new DNG.

That could be an acceptable workaround. You're usually hard-pressed to see significant differences between lossy and non-lossy DNGs even when pixel peeping at high magnification.

my Ricoh GRIII DNG raw files do not work with Enhance Denoise in Lightroom Classic 14.3.1

Denoise works great with my other cameras Lumix GX9, Lumix GH5ii, Sony A7C, Sony RX100iv

Not an optimist about LR Denoise and the Ricoh GR IIIx anymore. Switched to DxO PhotoLab a while ago.