I love cacio e pepe. It's such an amazing dish for how simple it is.

One thing that can be tricky is keeping the emulsion smooth and not suddenly have the cheese turn chunky. What I've found very useful there is to put aside some of the pasta cooking water and then blend it up with the cheese on the side using an immersion blender. When you reach a good level of creaminess, you pour it back into the pot with the now drained pasta and use the residual heat of the pot and pasta to slightly reduce it down to the perfect level while constantly stirring.

This should make the whole process a lot more reliable while not changing the flavor by adding more complex ingredients.