Why everything is so bright?

As you can see in the image below, the map looks really bright. I tried to change some settings that I saw in tutorials to make a night sky, making it darker, but this does not change the actual brightness of the game. What do I need to change to make things less bright ? Thanks.

Have you tried adjusting these on the camera:

The default settings are somewhat aggressive.

Where can I find this ‘camera’ ?

It’s a setting in the post processing volume.

There is no post processing volume though. Should I add one?

Yes. You can make it’s extent infinite if it’s supposed to cover the whole scene.