The “too dark” portion reminds me of this AFAIK still-extant bug… perhaps that’s what you’re seeing?
Editor has a bug with lighting if you auto-bake.
The current first scene will look correct, but when as you load or reload a scene, that subsequent scene will be darkish and potentially have other lighting issues as well.
You can verify that this is the case here by making a build to play outside of the Editor.
Turn off auto-bake and bake your lights if you wish to see correct lighting in the Unity Editor.