There are a few more suggestions I can think of to fix your issue. I do want to re-iterate your issue to make sure how to fix it. You are still experiencing the ‘washed out’ look similar to the second picture you posted? This image seems to be like the first one you sent on your post which is why I ask.
Either way there are a few things you can try aside from the suggestions I have made already.Firstly you can add a Skylight into your scene. The Skylight serves as an ambient light fill which can have a color applied to it. When you add this Skylight, change the color to a dark grey or even black. This will darken the ambient lighting in your scene.
Similar to this, within the ‘World Settings’ tab, you can change the ‘Environment Color’ to a dark gray or black. Keep in mind however, this will change the look of your entire world instead of just the the ambient fill light, like the ‘Skylight.’
White Environment Color
Black Environment Color
I hope one of these suggested fixes resolves your issue.
Thanks,