That's because it's a super high res crop
I'd imagine that this would be a near +150% crop of the original image, easily. That's what heavy crops look like.
I don't know if David binned the image; it would have been beneficial for SNR , but it's definitely not unfocussed IMO, it's just heavily cropped in.
David are you able to post the original image as well prior to cropping? It would also help with advice about processing. I'd be interested to see why you've got that black artefact around the object.