Need help in replicating the scattering effect within the meshes. Path Tracing

I have a task to make elements that repeat the glow on the screen. The triangle cells should repeat only one color.
I have created a ‘Media texture material’ which is animated using sequences.
But the problem is that the intermediate colors have low intensity + dark areas.
I tried via ‘Opacity mask’ to exclude black and dark colors, but it generally has a bad effect on the overall glow.
How can I replicate the effect of spreading the glow inside the mesh as in the video and have the triangle remain light when there is no glow.

Reference:

my current result: