> In my head the AI should be able to get the weakest students a bit higher

I think the evidence so far is all students lose learning and cognition, but the brighter students lose less.

Based on the paper it hits harder on the brighter

From https://cepr.org/publications/dp21577 :

The losses are largest in social science subjects, followed by STEM and languages, and are especially large for junior students, high-achieving students, and boys.

No mention of the weakest student. Which probably means they did not have a significant worse or better score