In general, it's still true that denoising a higher quality input will yield a higher quality (closer to resolved) output, so all you have to do is wait a littl

In general, it's still true that denoising a higher quality input will yield a higher quality (closer to resolved) output, so all you have to do is wait a little longer. Denoising is typically applied in interactive environments where you don't get a static result, you get a new denoised result that includes more samples every frame. Undersampling is easy to spot because the denoised image jumps a lot every frame. Once it stops moving a lot, you can have a lot more confidence. So the problem you're citing is not one that you're stuck with, and it's not a problem in practice.