We've done it before. Over a century ago, tuberculosis was same killer that Covid-19 is today. So the same question arose: how can we send our children to school without making a lot of people sick? The answer was to change where school was held. It was actually done outdoors, in the sunlight (with canopies), where fresh air breezes could help blow the contagion away. It worked.
It is hard to believe, even with a president and other people in positions of power denying the findings of scientists, that we could not do as well today. Here's a picture of what New Yorkers did to teach their children over one-hundred years ago:
That's class, being held on the deck of a ferry boat. Manhattan is behind them, to the west, and that's the Brooklyn Bridge, upper right, to their north. They are on the East River. On a boat. In school.
Yes, they are too close together by the standards we would use today. And they don't have masks on, again because we know more about stopping infection than our great-grandparents did. But what they knew and did worked. We could only do better.
Worried about the sun? Use a tent:
Worried about the cold? Use an "eskimo bag" and a block of heated soapstone under the feet:
Keep the windows open for anything indoors. And have lots of windows:
Or just stay outdoors:
Remember, this was all done by people with a fraction of the knowledge, technology, and resources that we have today. Our great-grandparents may be watching. Let's show them that they taught us something, both in those classrooms through our parents' parents, and through those pictures, to ourselves and for our children.