Quite a quandary there.....
You can even see the tiny veins still intact. The mass inside does look like unabsorbed yolk (and bad yolk at that). Probably a twisted cord. I would lean that way especially if it is the only baby not coming out of the egg.
I would personally try to save it and be prepared to tie off a cord.
I just had a hatchling crawl out of the egg and it had a HUGE yolk still intact. So large the hatchling could not pull it out of the egg!! I was worried the hatchling would cut the cord on the egg, so I removed the baby and yolk and put it in the warmest tub of my hatchling rack. The cord was twisted a few times. I rotated the yolk so the cord was straight and the yolk is already half the size after one day. Hatchling is still on high alert. Looking great.... just a bit lethargic.