One of the great advantages of using the Sharpening tool inside Lightroom is the Masking option. You can avoid enhancing the details in the flat, smoother and darker areas of the image where the noise and artifacts like to hang out!
Also within the Details section are two noise reduction tools - Noise Reduction (luminance noise) and Colour Noise Reduction.
Colour noise reduction
My editing process typically involves colour noise first. You can see this when the blotchiness has random colour. A more technical term is mottling artifacts.
First, move the smoothness to the right then adjust the Detail slider to recover any details (fine lines) lost. It is a real balancing act between the two sliders. You will rarely need to go above 25 in Smoothness.
Now you have three sliders to balance!
You will need to zoom in to see the effect of your adjustments then zoom back out again to make sure it still has a sense of realism.
The Contrast slider protects the contrast in the edges of the objects in the photo. Details is adjusted to bring back details lost when adjusting the Noise Reduction slider. Again, it is a balancing act.
Tap on the preview window outside of the actual image to fill the screen without distracting menus.
Tap and hold your finger on the image to preview the image before making all the Detail adjustments.
Swipe your finger on the zoomed-in image to navigate to another area of the image.