911 was very traumatic. the first major act of international terrorism in the US. All those sudden deaths. All the horrific video evidence.
Covid has of course been more gradual. Seemed like a distraction at first. But it certainly changed our way of life much more than 911. 911 never closed America the way Covid did. And although 911 presented some unknowns, the fear of the unknown with Covid is unprecedented. Finally, the political division around the Covid response is so much worse than after 911.