It seems an unlikely field to get a doctorate in, but - a little online searching and sure enough, there's an institution that will accredit you.
Link: https://www.metaphysicsinstitute.org/program-info/specializations/cryptozoology
Note they also offer doctorates in Para-Anthropology and UFOlogy.
I mean, if you have the money and inclination surely someone has the Obligation, nay, duty even, to accredit your studies and take your tuition.