According to Wikipedia there is a list of those attended:
Neither Putin nor Zelensky are on that list.
Additionally, Young Global Leaders has rules:
Candidates must be younger than 38 years old at the time of acceptance (meaning active YGLs are 44 and younger), and highly accomplished in their fields.
YGL was founded in 1993.
Putin's birth date is: October 7, 1952.
In 1993 Putin was 41 years old, three years too old to enroll in the founding class of YGL.
Official Link:
The stink of crackpot conspiracy theories is strong on this site.