Hi @Melik1,
While @Only-Preston is correct that the direct effect of coloring shadows is not directly achievable since Unreal prioritizes physically based lighting, there are some visual workarounds that I would like to offer as options.
The first option is to simply adjust the color grading for the shadow range in your postprocess settings. This will not just directly target your shadows unfortunately, but depending on your project this might be good enough.
Another option is to separate out the shadows in a postprocess material. Again, this won’t be entirely accurate, but it will allow you much more control over what receives color. In my example, I’ve used a smoothstep and a multiply to hone in the mask, but you can use other math instead to achieve the exact look you need.
Unfortunately, yeah without modifying engine code this is about as good as you can get.
Good luck. Let me know if you have any other questions.