I don’t have a guide, which would be really nice for that in my estimation too. I learned by changing settings and seeing the effects, and repeatedly reading the doc page on those things. I’m missing some things too, in my knowledge, and don’t remember everything when I’m doing it. It requires some amount of practice to remember and understand the different facets to get specific results and improve them, and is something I need to do too.
So, is the wide, orange thing in picture 1 (without atmo fog) the sun? I think it is appearing to not be fully below horizon, which I think is probably due to the 20:00 sun time, at least partly. What is the latitude and longitude? The darkness level looks correct for that picture. Are you able to share the project? Simply right-click the project folder it’s in and select “Send to > Compressed Folder” and confirm to place it on the desktop. It’s the easiest way to zip it and share it because it’ll be a far smaller size to upload to the forum thread. I’ll look at it and see what I’m capable of doing to fix the two issues of the weird sun and overexposed atmospheric and height fog.