Why Is Opacity in 3D Widget rendered differently from screen space ?

I am using widget component for 3d widget and opacity is rendered different from screen space. I changed blend mode to unlit and then isn’t it supposed to be affected by lighting? But It is affected by lighting even without directional light (My world has only spotlight).
I tried eye adaption node so color is quite similar but opacity is really different. I just want the opacity looks similar to the one from screen space or when it is attached to HUD.