Nobody's mentioned it yet, but one of the big things I personally suspect has been keeping people at home rather than job-hunting is the child tax credits. Those are ending soon so some of the people who figured that was enough to stay home on will start looking for other options.
Unfortunately a big part of the problem is Boomers retiring, as well as all the people who've died during the pandemic, whether it be from Covid, neckroping, ODing, or what have you. These people aren't coming back no matter what anyone does. The recent cost-of-living adjustment to SSI will keep retirees from feeling the pinch of inflation for a bit longer, and if any Boomers do go back to work it's unlikely to be at a similar job to those they left. Probably more something part time to supplement their SSI.
Workforce participation rate is apparently the lowest it's been since '79. It's really great we trashed our economy over the flu.