Your method seems to go backwards with mine. I don’t understand why your results is so different from mine, I am just stating that from day 1 NLM has been giving me this result:
That was how it ruined my first render of the 2.78 version donut scene. After that I have been avoiding using Blender’s denoiser and use some third-party software instead, until 2.81, the AI denoiser, it was such a big news
EDIT: Look here Blener Guru once stated this:
