I found a tool to help skim through a long series of FITS images, looking for clouds or image shift:
https://remoteastrophotography.com/2022/05/preview-fits-files-using-quicklook-for-windows
Once its opened from the File Explorer you can look at the images as fast as you can hit the down arrow key. And if you hold that key down its starts showing about every 10th image.
I had 10k images to review; wouldn't have been possible without a tool like this.
George