I would say that the 2021–2024 Synod was a "first" in many ways.
Notes from Wikiquote
It was the first time that the entire Church—and everyone within it—had the opportunity to participate in the synodal process. | It was the first time that non-bishop members participated in the Assembly. | It was the first time that a Final Document was immediately approved by the Holy Father, thus becoming part of his ordinary Magisterium. | From an interview of Andrea Tornielli, Cardinal Grech: A new path to help the Church walk in a synodal style, Vatican News (March 15, 2025)