It was possible in other countries.

My children (Quebec) were in class all of last year, except for a 10 day period in January - the tail end of a local lockdown at the height of the third wave.

Infection rates were certainly higher due to schools opening, but other decisions - and a population that was mostly tolerant of restrictions - mitigated that. We wore masks, we limited contact and we stayed home to the extent possible. As a result, schools were able to stay open.