I think it is time to get rid of hqdn3d denoise filter. I really do not like how this filter shifts content of the frame. KNLMeansCL does better job here. Open images in separate tabs and you will see what I mean.
Original frame
MDegrain2 + KNLMeansCL (strength=2)
MDegrain2 + hqdn3d (strength=8)
Another my conclusion is that KNLMeansCL is not very useful as standalone filter.
Original Frame
https://i.postimg.cc/JnR8rB49/org.png
MDegrain2
https://i.postimg.cc/brdKr0XF/mdegrain2.png
KNLMeansCL (default settings)
https://i.postimg.cc/PrgBf8S2/knlmeanscl.png
hqdn3d (Strength=8)
https://i.postimg.cc/7hy2Y9Tq/hqdn8.png