Her anxiety levels went through the roof. Thankfully we didn't get to an extreme case of suicidal ideation but things were pretty bad for a while. Medication has helped, but getting a therapist appointment is nearly impossible. They're 110% booked.
What we understand is that during the shutdown the 'alpha' girls all coalesced on social media and shut everyone else out. They also took vacations, had slumber parties, and did a ton of things that everyone else was avoiding because those families tried to listen to the current advice.
When the return to school happened these cliques instantly had fresh prey: the unconnected, the minorities, the non-english speakers, the ones that didn't purchase new clothing over the lockdown, the ones that didn't go to the slumber parties and vacations. And half of your friends/allies were in the other side of the alphabet and working from home.
This is all stuff that boys of this age don't care about. But the girls are vicious. Two of our friends have physically relocated out of the district, two others are going to change schools.
TLDR: Preteen girls are awful, and always have been, but the lockdown concentrated and amplified it to horrific proportions.