So during 2020 we moved into a model where we recorded the lectures for students to watch on their own time, and then they'd have a questions-only class (or so they were told). This turned out to get 80-90% of the students to actually view the material before class, and then they'd ask questions about what they didn't understand. On a few difficult topics, we ended up having yet another lecture (but focused on the parts they had trouble following).
On some occasions where they didn't engage with many questions (I think it was the first few classes under this model, which was novel to the students) we the teachers picked up on doing a quick recap and focusing on what we knew beforehand tends to be hard to understand, and engaged them in the class (questions, explain the concepts themselves, etc).
Here's my take: it takes a lot of effort to do this, from recording the material beforehand, to "lying" that the class will be questions-only for clearing up (and we know we'll end up explaining yet again if they don't bring questions), to actively engaging and changing the pace of the lectures/classes.
Because of all this effort, out of 5 different courses I teach, I only managed to pull this in 1, and we're still tweaking a lot of content to make it work better under this model. But we're planning to keep it even after the restrictions are gone (we're still not giving in-person classes at my university, in theory they'll be back for 2022).