While I do think this is likely a factor, I would argue that we are most likely also in the midst of a paradigm shift for the CBM genre as a whole and its standing with general audiences. It's not just that Blue Beetle bombed or the other DC(E)U films that have released so far this year have bombed IMO, it's that we are also seeing the MCU continuing to struggle by and large at the same time.
Obviously it isn't like the genre is entirely dead and that audiences have lost all interest in superheroes suddenly; both GotG Vol 3 and Across the Spider-Verse did really well this year, as did The Batman last year. But I think we might well be at the point where the CBM bubble of the past decade or so has finally popped a bit and the point where general audiences no longer have much interest in full-blown cinematic universes where every new CBM is connected to a larger web and has to go see a superhero they know nothing about yet.
The pendulum might just be swinging back around to where it was in the 90's and 2000's, with audiences primarily wanting self-contained CBMs that primarily focus on well-known and established superheroes.