Assuming that I was correct, it could be from Nijisanji's "LIGHT UP TONES" AR live concert, which is happening around uh... back in 2021 or something. As far as I know, it's only available as either Blue-Ray Disk available on their shops online right now, or in select covers that was done and uploaded by the talents participating, like this one:
That specific one in the screenshot might be from the ones that isn't available as covers uploaded by the talents (I found a playlist of 16 videos but only three exist, the rest hidden/privated). I will assume that, judging by the screenshots, the Niji staff and EN talents are discussing something related to their doomed AR Live. Maybe showing the EN talent that their AR live would be similar like this?
Also curious me decided to check what they used and they seems to be using Microsoft Teams? That's something new aside of Slack and Discord.
EDIT: Shu talked to Alban about how he gonna "PERFORM", so it's definitely about the EN AR Live concert.