It seems to vary. Our district has our kindergartner in front of a screen for about 2 hours (not continuous). Then they give us activities to do with our kids,

It seems to vary. Our district has our kindergartner in front of a screen for about 2 hours (not continuous). Then they give us activities to do with our kids, at our convenience, that we submit via an app. The teacher reviews and comments on it. There's around 7 per day, but they aren't too difficult for our 5 year old: write 10 T's, read them a book, collect then count some stuff, etc. Our school is 100% distance learning. When they were going to allow distance learning and in person, they were planning to have completely separate classes for this so they could better optimize for your particular medium.