I have a junior in high school and a sophomore in college. The sophomore is a japanense/linguistics major and has to log into the japanese class 4 days a week. Other than that, teachers are recording lessons, uploading videos that teach, assigning readings, and giving work. They do about 1-3 hours a day of work.
THe reason being exactly what was explained before. We are not allowed to require the kids to be online at certain times because it creates inequities in access. Some families have 3 kids and 1 device. Who gets to be online? Some families have spotty internet or no internet. Some families are not in a place to access this. I have 2 families where the dad is a nurse and the mom is also still working full time and for them, trying to figure out when and where to do the school work is near impossible. Even in our family, where we all have a device and decent internet, there are times where we struggle. If my husband is on a video call, and I am on a video call, and the kids get on video calls, the service gets spotty.
So teachers record lectures and put them up for kids to watch when they can. They put out notes for kids to take notes on or for kids to read. They do assignments and turn them in. Teachers are available for support in live office hours as needed. So the kids are not on their own, they just have the flexibility to do their work when it works for them and their family.