Correlation isn’t causation, I agree, but the signal here is extremely strong (data from 71 countries is included in just one graph of that file I linked) and we seem to understand the mechanism that would cause screens to lead to poor learning outcomes (a breakdown in sustained attention).

you could write that same paper but replace ‘EdTech’ with climate change, and (technically) be eqully as correct.

That is false, because you’d have no comparison group. You can compare outcomes of kids with and without tech, but not kids with and without climate change.