Lack of color when stacking RAWs

Hi
I always struggle to get good color when stacking with Siril.
Ive been doing more milkyway shots lately. I open the RAW image in PS and I like the overall color. I usually just stack 4 wide angle images.
If I convert the images to tif first in ACRAW and then stack them in Siril (no darks, bias, flats), then the image looks very similar to the original image in PS. The color tonal range and temp is the same.- All good!

If I stack the RAWs with Siril, then the image comes out with minimal and different color. I color calibrate the background and remove green noise, but the color is washed out. Adding saturation in Siril does next to nothing. So I bring the image into PS and do curves adjustments and try to add color saturation etc.
But I can never get close to the original color of the individual images.
Any help would be great thanks