Hey @solymi thanks!! To get the most details and cleanness, you need to give the Ai as much info as you can (given the word limit, which differs for each software).

Also I often go through several phase of remastering, you can use something called GFPGAN to fix the faces and hands, and I also use photoshop to clean certain things.
Then I use another software called GIMP to alter contrast, saturation and sharpness.