I don't know whether that is a factor. I'm a noob, like you. Hope, someone else sheds light into your question.
You could try something in DSS with the existing data:
set the star detection threshold (Advanced tab) higher to (possibly) tidy up that bright blob in the middle of OC.
or/and reduce the number of images chosen by DSS to 60 to 70% (main registration window)
maybe that helps and you can enjoy more what you already have.
or just take one single light frame against your darks/bias?
please, someone else - enlighten us.
