For Mac, Lunar (brew install --cask lunar) gives "sub-zero dimming" that works perfectly -- it hooks into the brightness keys and gives a whole second, lower menu. The lowest setting is actually too dim (as any lowest non-zero brightness setting should be...) Works for external monitors, too!

There's no Reduce White Point on Mac as far as I am aware. However, you can use the fantastic Lunar [0] app to achieve this, as it supports "Sub-Zero Dimming".

To use it, I think you just need to start Lunar, and then press the Reduce Brightness button on your keyboard until it goes below the minimum Mac allows.

[0] https://lunar.fyi

https://www.pangobright.com/ on windows is great, albeit a little weird. I think it makes a transparent always on top window that doesnt take events. System right click menus and stuff seem to no be under it.

But I still like this over flux and the likes

https://lunar.fyi/ can do that (as well as control brigthness on external monitors)