“ Judging by the deformation in the wing root, they may have picked up some debris from the runway that lodged under the slat when the slats were retracted”
Interesting you say that. I thought of it as a possibility too, ala Air France 4590 (Concorde that crashed). Maybe the nose wheel went over something and sent it flying toward the slat but there is no precedent for such a thing happening in the US. Our maintenance standards are higher than in other countries, or at least have been up until now. But when you consider all the recent problems plaguing Boeing and United I am leaning toward some diversity/ DEI connection.
I wonder if it is a delamination... that would be a significant cause for concern fleetwide for all carriers using that airframe.