OK, so I ran this through my workflow, which is as follows:
0. Open in Photoshop
with no prior adjustments other than cropping in Lightroom
1. Topaz Denoise AI
2. Camera Raw Filter
3. Local dodging and burning
4. Add blur to background if needed or desired
5. Topaz Adjust AI to sharpen
OK, with yours I simply used 1, 2, and 5.
Here's the image after Denoise and Camera Raw:
Using Denoise I tend to leave the Denoise slider at 15 (which is usually enough to deal with ISO 4000 on the D500) and bump the Sharpen slider to anywhere from 20 to 40. I then look at the preview in multiple locations to see what I have. I do not touch the Recover Original Detail or Color Noise sliders unless I see detail going away and the obvious evidence of color noise, which I rarely get. The noise in this shot was soft but there are lots of small details so I ultimately went with Denoise at 10, Sharpen at 40, and 0's for the other two.
In Camera Raw I then did light and curve adjustments, boosting exposure and pulling back highlights making sure that I have the blowout indicators set so I can tell when I'm losing light information. I also bumped the Vibrance, Texture, and Clarity sliders to see what I got with no other filters. Here are the settings (Curves was just a very small 'S')...
I would be happy with it at this point, but I decided to mess with Topaz Adjust AI which I
much prefer to Sharpen, both for its effectivity and it's ease on CPU.
So here it is after applying some additional detail extraction/sharpening in Adjust...
Here's the settings from Adjust ...
With rare exception I only use the Detail section of Adjust.
I don't see grid lines, so I'm wondering if you did some light adjustments in Lightroom before opening in Denoise? I find Denoise to be less problematic when it's the very first thing I apply. If I have an overly dark image I can sometimes get pixelated weirdness after Denoise so if I do then I'll use a levels adjustment layer first to brighten, nothing else, and then merge to a new layer to apply Denoise.
I have Sharpen AI, but as I've said I
only use it to fix the original sharpness in an image I need to have that is just soft to begin with.
Please let me know if y'all are seeing the 'grid lines' because I am not.