A noiseless Cycles render without super high samples that will take days to render and without post editing would be a dream.
There are already denosing methods that do a pretty good job at removing noise without removing too much detail and making the image look blurry or distorted.
There is even an AI-Accelerated denoising tool by NVIDIA which performs perfectly. It’s almost unbelievable how it can take very poor sampled noisy images and still make them look fine as if they were high sampled.
Unfortunately, this AI-Acellerated Denoiser works only on NVIDIA GPUs since it uses the OptiX Engine which relies on Kepler, Maxwell, Pascal and Volta graphics cards. So AMD GPUs or NVIDIA GPUs that are below Kepler can’t use it.
But I think there are other good denoising mechanisms out there that would make Cycles make more pleasant to use without the annoying part of the noise.