[sytelus]

Windows 10 now also has night light setting specifically to reduce blue light emitted from the screen and better sleep! With just press of a button it would automatically go to "night light" mode from sunset to sunrise. Very cool. I think iOS also has similar setting. Plus there are lot of "blue light" blocking screen protectors out there but most of them are from China and hard to tell which one really works.

[Fnoord]

Nowadays, latest versions of Android have this native (called LiveDisplay in LineageOS), macOS/iOS have this native (called Night Shift in macOS). Windows 10 have this native (as you already mentioned called Night Light). Windows was last btw.

There was a time where F.lux was basically the only way to reduce blue light. BTW, F.lux has more advanced options than any of these OSes but it requires rooted device on Android/iOS. For macOS and Windows it will work out of the box.