How about using a backchannel to have quiet students engage more? You could “require” them to submit a comment or question at regular intervals (every 15 mins?) to metacognitively reflect or to get clarity or ask for help.
I also know that first days can be tough. I tend towards team-building activities on the first day. This year, we built towers out of spaghetti and marshmallows. I’ve also done more academic tasks that have them collaborate and get to know each other. Gives me a lot of information about class dynamics and their ability to lead/follow effectively.
Then I send them home with a video and a written set of policies they need to review and sign. It includes stuff about “what is a flipped class?” as well as what to expect from me as a teacher.
I like that WAY better than when I used to stand up and talk forever on the first day.