How do i do that?

Easy though tedious task to do, but a bit trickier to explain.

You should open any single EnvColors_*.cfg file in data/Env folder of the brighter nights submod and compare it with the corresponding files in the base mod, in order to see wich settings of the base mod are modified in brighter nights. You could do it manually in notepad, but since there are hundred of entries in those files, I suggest you to use winmerge for making this task a lot easier. After doing it, you should open the cfg files coming with the skycolor hotfix and merge in it the modified settings from brighter nights, replacing the relevant settings. Once more, winmerge is your friend.
Once finished, you can enable the modified Dynamic Environment SH5 v 2.1 - Skycolor Hotfix #1 after the basemod, and you won't need anymore to enable brighter nights :up:

Ah english is not my native langauge so im struggeling with this.But what u are saying is:

Brighter nights -merge- base mod,and then
Brighter nights -merge- Skycolor ??

It is not exactly that simple. The base of the idea is to compare the files in both mods and make sure that the .cfg files which control a lot of the settings are compatible and take into consideration both mods; no double values, no values restricting or contradicting other values.

That is why gap said - very tedious work.