I agree with you: Photo AI is very good at some things, but I still get better results and prefer DeNoise AI and Sharpen AI as needed compared to Photo AI, if I’m working on new Raw images.
I use Lightroom with it’s Photo > Edit In to send the photo out to DeNoise AI. You don’t have to use DeNoise as a standalone app. Now when you use Edit In in Lightroom, the image comes back as a TIFF, not a DNG, unlike Lightroom’s File > Plug-in Extras > Topaz Photo AI, which can come back as a DNG; maybe that’s what you’re looking for. I would prefer that, too, although I’m starting to see people say try exporting from Photo AI in TIFF not DNG, as it may be more effective that way. I haven’t tried it yet though.
Anyway, I’m just a user like you with no inside info, but my guess is that Topaz is done adding features like you want here to the apps like DeNoise Ai. For the moment they are focusing their programming firepower and subscription marketing on Photo AI and Video AI.