How to set monitor to make it less harmful to eyes during the day?
is blue light also harmful during the day? if yes why not just turn blue to 0 in RGB settings of my monitor? would it be also helpful during the day?
No, blue light is good during the daytime. The sun is very very very full of blue light. So, during the day, there's nothing wrong with using 6500K unless your eyes feel better with warmer color temperatures. However, consider lowering your monitor's brightness before using a warmer color temperature during the day.
For me, "during the day" can be in the middle of the night because I don't have a consistent day/night sleep schedule. So for me, "during the day" is simply "while I'm awake". "Night" for me can also mean, "I will be going to sleep in a couple of hours", even if it's the middle of the day and bright and sunny. I just block all incoming light, dim my room lighting as much as I can tolerate, dim my monitor as far as it will go, and I switch to the warmest color temperature that I can tolerate. An hour or two later, I"m ready for bed!