OK. I had you turn off the automatic bump because it is using normal mapping to replace some detail that you would get from true displacement. That allowed you to see what’s really going on. You should almost NEVER need to go to 16 subdivision levels in the RS tag. You either need to subdivide your original mesh, or put it in a subdivision generator (used to be called Hypernurbs I think)
Barring that, I would like to ask…do you really need displacement for this? or could you get away with normal mapping? (And I don’t mean the kind automatically created in the displacement settings, but rather building normal mapping using a normal map and the bump map node piped into RS material…overall…bump.
I personally find the displacement in C4D when using Redshift to be a bit wonky.
It is usually best to have some antialiasing in your maps, rather than straight from one color to the next, which can, and most likely will cause stair stepping.
I don’t believe your lighting has anything to do with this issue.
If you could post a small sample file, we could take a look and get a better idea what is going on.