You might as well conduct an experiment with apples. Add 2 and 2 apples and check if there's 4 of them now. Max Planck implied the study of the unknown laws of the universe, not a computer program like DxO or Topaz denoise, created by humans.
DxO denoise isn't a black box. DxO developers know it better, but we already know how it works in principle. You don't need to do experiments in order to conclude there's 'fake' detail. It's just a given that this software generates/guesses the detail because it's how it works. It's not matter of experimentation, it's already a mathematical truth.
I understand DxO works great for you - it's a great tool indeed, but you're missing my original point (see above in the thread) -
sensor performance comparisons are not done on heavily processed images with generated/guessed detail. This rules out software like DxO, Topaz etc. and any other noise reduction software with or without AI.
Ok if you really need a visualisation, here it is. The images from DPR scene comparison - raw images from the R5II at ISO 100 and 25600. They illustrate the loss of detail and what I call 'fake' detail. It's your beloved DxO.
Unprosessed images. R5II, ISO 100 vs ISO 25600. Obviously, at ISO 100 we see more detail, the text on the thread rolls is readable. Not so much at ISO 25600
View attachment 221160
Imaged processed in DxO PureRAW 4. R5II, ISO 100 vs ISO 25600. After processing, the text is still readable at ISO 100 and still unreadable at ISO 25600. It's kinda sharp and looks
plausible at the first glance but doesn't make any sense if you try to read it. Thread loops are not separated and almost completely lost. That's the generated detail.
View attachment 221159
So above you can see an illustration of a very simple fact: DxO cannot actually recover information that was lost. You can see the difference between 'more' information at ISO 100 and 'much less' information at ISO 25600.
However, if you try and measure the visible noise (as standard deviation) in the images on the bottom, it'll be roughly the same. Not only we lose information in the images, we also lose any usable information about the sensor's performance.