At this point, you most likely will need to consult with a tax professional (link below) and legal counsel.
https://taxexperts.naea.org/
At both the point of purchase and sale, a Form 8549 probably should have been filed.
See https://www.irs.gov/instructions/i8594#idm140044360310576
Regardless, there is no option to "defer claiming the purchase price until this year".
