Flipped classroom was a popular method when I was teaching math. Some students found it very helpful. The trouble was getting the students to do the reading before class. If students came in unprepared they struggled to keep up.
It's especially hard when multiple subjects try to do it, because it can add enormous amounts of home-time expectations. And many families can't dedicate that much time.
I do like it though, and I like that college generally leaned that way more (and was better balanced, as it had substantially less time in classrooms, so you could study during the day).
I taught a flipped classroom online. Students had to successful pass a quiz on the before class materials to get the join link to the session.
I did this for the last college programming course I taught (2025) as an anti-LLM measure. Every class started with a very short closed-book auto-graded multiple-choice test on the reading. I was careful to specify which was the core reading needed to learn the material (on the quiz) and which was extra (not on the quiz - I think many professors assign this extra reading to everyone, thinking of their strongest students). I think this developed an expectation in the students that doing the reading was easier than finding a way not to.