we have a little plugin for using the INTEL denoiser in c4d 18-21, also with RS (use bruteforce in that case and no filtering).
it works very well denoising fine but very visible noise, to no noise and also blending it with original for tuning to let some rest noise stay.
the advantage is you can denoise also images or series of images from disc after rendering,
so this works non destructive and is an easy tunable denoising result in post at a low price.
it is winows only for now, it might interest some RS users.
i use it often for my projects with various render engines, due the easy workflow, it denoises direct in the c4d picture viewer, so i not have to leave c4d (also if image sloaded from disc are used)
you find it here for only 29.- euro, permanent life time lic: