From the quoted CNN article: "...the generous pandemic-era unemployment benefits that have already ceased in multiple states will run out in September, which could affect the rate of hiring as well."
Part of the burnout (certainly not all, perhaps not even a majority) is the extra load working Americans are taking to offset the voluntarily unemployed.
Somehow, I suspect many states will extend these benefits beyond September until Congress & State legislatures can enact legislation that assigns benefits to those truly in need vs. electively unemployed... if that's even possible.