According to that guy on the CompetitiveWow reddit that aggregates the numbers, week 3 of season 2 had 3.33% fewer dungeon completions compared to season 1 week 3 (and is still higher than 2/4 of the week 3’s in Dragonflight).
So like, yeah, but… is it really a significant enough amount to be all doom and gloom about it? If their chart is anywhere close to accurate, season 2 so far has had fewer overall players but also a much better retention rate within the first 3 weeks compared to season 1 (and somwhere around the average of retention rates for DF & TWW).