Material properties

My Problem:
Im making small project. It takes place on floating islands in the sky, I want the game to look vibrant and maybe a little bit cartoonish.

But recently Ive run into one problem, because I wanted to achieve that vibrant and colorfull look, Ive set some of my materials to have emission and it worked and looked completly fine, until Ive decided to inplement day and night cycle to the game. The materials are emissive so they are glowing at night, which is not exactly what I wanted.
Ive tried to remove the emission property, but it looked awfull. I also tried using HDR, which was also looking like garbage. Ive also tried adjusting texture itself, but I just cant surpass certain level of vibrance and brightness, even if my texture looks very vibrant and bright, material always ends up looking washed-out and dark.

My Question:
So, is there any way, to achieve the “emissive look” without actualy using the emission property?
Btw: I was thinking about changing the emission value from the “day and night cycle” blueprint, is it a good idea?
Theres an image how it looks:

You can make everything much more colorful by including a post process in the scene. Drop one in, set ‘infinite extent’ on, and then change the saturation to about 1.25 to 1.5.

Yep I could, but I chose not to do so. The problem is not just about saturation, the colors dont match either. Yes and I can do it all in post process, but theres a problem, post processing will apply to whole screen not just one specific mesh. I dont want to tweak the look of whole scene, I just want to correct that 1 particular material.
So is there any way to make that material look like the emissive one without it being visible in complete darkness?
I know I can for example set it to unlit, but that will eliminate all shadows (I need some shadows)

What about the saturation node in the material? ( desaturate with -ve param )

Ok I´ll try, but what about those dark shadows on bottom?
I want shadows to be casted just on top, not on the sides

Sorry, not sure, not my area really. Maybe try posting again with a clearer target, there are a lot of people out there aiming for this kind of look.

Yep, I will. Thnx for your time