[dumb question] Can lightsources be modded?

[MWatevr]

Hi, I've never modded a game in my life. Can lighting be modded? I don't think that post-processing would be enough, Reshade just looks like filters that don't change nearly enough, but I don't know for sure.

I assumed that some of the lights are real lamps and I wonder if they can be edited.

 

Specifically, I hate the way that some outside areas look and would like to see what the world would look like with different strengths of the sun, as well as what is actually affected by the sun. Maybe materials or textures can be edited to react differently to light?

 

Thank you for reading my dumb question. I thought it wouldn't hurt to ask.