There's a reddish tint at the top edge if the image. It looks like a gradient residual first, but further to the right it suddenly turns right and runs across the image.
What i like is the missing of the typical Andromeda gradient-artifact ~90% of all Andromada Galaxy images have - when the complete galaxy sits within a dark donut, resulting from improper processing

I am very new to astro post processing, so I may not have complete context. When I used background removal in pixinsight (either using dynamic background extraction, automatic background extraction, setiastro - which ever method I tried, and however accurate I tried to be with the placing of squares/sizes/thresholds), I would have that donut which you are talking about. SO i ultimately gave up and did not bother with the background extraction in pixinsight. Moved straight to spectrophotometric color calibration, noise removal, followed by histrogram stretches, masked adjustments, etc. I did try deconvolution, maybe that is why the stars have black edges around them?
That is why the gradient still shows up.