As you said, Vito and Yianni both took an Olympic "RS" in 2020 by unenrolling (the only way to do it in the Ivy League), and then both unenrolled in the 2021 COVID year. The latter was an explicit exception: they changed the "4 in 5" (not "5 in 4!") to "4 in 6" for this one time. AFAIK, nobody else would have been able to take more than one year.
Josh Saunders has two empty years in his wrestlestat history.