Still some hidden slack in the labor force.
Back in 1998-2000 (just before the dot.com crash), some ppl were changing jobs every few months to get up to a 20% (or even more) bump in pay. Today? Not so much.
Employers have gotten "used" to not having to pay up and, if they can't fill a position, are more likely to let it go unfilled than increase the salary above what some algorithm tells HR is the "going rate."
As for labor participation rate: the trend is not good for males in prime working years (24 to 54, I believe). Some posit that low marital rates are a factor (marriage/family/babies tends to spur workers, esp. men, to work more hours, seek higher-risk/higher-reward positions, etc.)
It's a weird world out there.
Also , recall that the previous WH administration changed how unemployment is calc'ed; the new admin has not reverted. Better to look at the U6 figure (which includes "underemployed" workers, part-timers who wish for full time and "discouraged" workers who have fallen out of the stats).