There is no way to accurately determine the cutoff date for the "Super Two" arbitration category. Because you have to wait to see what players qualify under this rule. Here is an explanation:
https://www.mlb.com/glossary/transactions/super-two
Super Two Definition
Players typically must accrue three years of Major League service time -- with one year of service time equaling 172 days on the 25-man roster or the Major League injured list -- to become eligible for salary arbitration. Super Two is a designation that allows a select group of players to become eligible for arbitration before reaching three years of service time.
To qualify for the Super Two designation, players must rank in the top 22 percent, in terms of service time, among those who have amassed between two and three years in the Majors. Typically, this applies to players who have two years and at least 130 days of service time, although the specific cutoff date varies on a year-to-year basis.