The images above picture the result in Siril using the Histogram Equalization rendering mode. Note the improvement of the signal-to-noise ratio regarding the result given for one frame in the previous step (take a look to the sigma value). The increase in SNR is of [math]\displaystyle{ 38/3.9 = 9.7 \approx \sqrt{119} = 10.9 }[/math] and you should try to improve this result adjusting [math]\displaystyle{ \sigma_{low} }[/math] and [math]\displaystyle{ \sigma_{high} }[/math].