A response to zen32156
I wonder if stacking images taken over a shorter time period may help.
There is an interesting video on Youtube by Peter Zelinka entitled “Editing Comet Neowise with Photoshop”. He mentions Deep Sky Stacker and not using sigma clipping average method to process images. Unfortunately I have only ever used an old version of Photoshop Elements so am unfamiliar with the software in the video which looks way above my area of expertise. However, if you look at the video starting at about 9 minutes in it may answer your questions or at least give you a few ideas. Others may also find the video of interest.