I have not spent a large amount of time examining the results at a pixel level, but I did do a reasonable amount of testing of DeepPrime before I started using it extensively.
In general, in pretty much every use case that I have looked at in detail, DeepPrime was not being over zealous. In fact in pretty much all cases I was very impressed at the results it was achieving.
If an area did look over smoothed, then it was because that area didn’t really have any recognizable detail in the raw file.
I have only ever seen one case where it did lose some detail, and that was a small amount of the detail of some very subtle texture of a plaster wall. Even this was minimal and more than acceptable.
What I have noticed is that at very high ISO (eg 54000) where the noise level is extremely significant, that the noise reduction at the default setting becomes notably uneven, which could give the impression of over smoothing. I don’t believe this is actually an issue though, its quite literally that the noise in the shadows starts to become more significant than the noise in the highlights. In this case I tend to dial the Deep Prime noise reduction down a little, allowing some more grain in the brighter sections of the image to balance the grain in the darker areas.