In this Unreal Engine 5.3 Niagara tutorial, we break down everything you need to know about the Initialize Particle: Color module! Learn how initial particle color works at spawn, how to adjust opacity and emissive glow, and how to create rich color variation across your particles. 
https://dev.epicgames.com/community/learning/tutorials/58qzd/unreal-engine-ue5-3-niagara-basic-initial-color-16