I tweaked this mod for myself, but since I saw a few people requesting this kind of mod I decided to post it online.
I did not make the mod myself, I just altered some settings. To create the effect I wanted, I used the SweetFX preset of K-Putt.

Basically what this mod does, is making nights way darker, and with that (unfortunately?) the shadows at daylight.
I also tried to make lights a little brighter, in this way players are happy to have flashlights on their guns and with headlights of the vehicles.
Ajust your game brightness to your own likings, I prefer having it nearly all the way down.
If you want to use the darker nights in an other preset, just copy the setting from levels and liftgammagain (and maybe bloom, if you want to).

To enable the mod ingame: press f12.

k-putts preset: https://www.gta5-mods.com/misc/reshade-sweetfx-graphics-mod