I mean this quite seriously because utilitarian body count calculations are made by the US government all the time, especially in the context of transportation infrastructure. What's a good multiplyer? 10000 kids educated per suicide?
Even if suicides were a thousand times more common, I think the advantages of an educated population would still favor keeping schools open.
Of course if practical measures can be taken today which suppress the suicide rate while still compelling kids to receive educations, I support those measures. But to do away with compulsory schooling to suppress the suicide rate is throwing the baby out with the bath water. With TikTok, there is no baby. It's all bath water.