Can't display Glow effects with CesiumSunSky (maybe a general question)


i try to use Cesium plugin with Unreal Engine 4.26.
I have created a bullet with a glow material.

The glow effect is visible if i put the cesiumSunSky at midnight (or if i remove the CesiumSunSky)

But if i put the cesiumSunSky at 1 p.m. the glow effect disapear.

This is my material:

I suppose it is normal but how can i force my glow to be visible even with bright background ?
i have tried to quickly add a very simple Niagara effect in my scene with Cesium and CesiumSunSky, and it is not visible.
i do not have this problem with a basic scene without Cesium.