First Saturday home game in 2023 was 41000 attendance, but it was also their 15th game of the season and they'd won 8 of their 10 games. Was against Tampa
First Saturday home game 2024 was 31,500, again, 15th game of the season, against Colorado. 4 and 6 over their previous 10.
Edit:
Follow up, last time the Jays had a non-covid 1st Saturday home game in March was 2019. Attendance was just over 25K. against Detroit