First of all, thank you for your answer! \o/
The assets I’m using is from this mega VFX pack : Niagara Mega VFX Pack vol. 1 | Fab
Here is the the link for only the ray pack : Niagara Ray VFX Pack (Energy, Ray, Hit Effects) | Fab
I’m slowly starting to find solutions, but it’s taking me a huge amount of time and a lot of workarounds. I doubt the system’s robustness afterward. In a way I’m relieved to learn that I was not the only one struggling so much with these assets haha