I'm using the Eevee engine and the fireworks are emissive particles, bloom is turned on. I tried both eevee and cycles, I want to use eevee though. I tried PNG with RGBA color, 8bit and 16bit color, no compression. I also tried TIFF with RGBA color, 8bit and 16bit color, no compression.
I want to render the images with a transparent background while keeping the color of the fireworks. In the viewport it looks normal, but when I render it and save the image it loses the color in the fireworks over the transparent background.
Here is a blend file of the fireworks and just simple cubes since sharing the models in the blend file is against ToS, but it does the same thing here. https://drive.google.com/file/d/1O-6VudxGP-Y_7jO09FVzM4IRjJEtTHQZ/view?usp=sharing