The U-6 unemployment rate includes the rate for folks who are underemployed as well as the folks who are unemployed but still looking for work.
Think of the damage done to that teen-aged and early-20s cohort in terms of work experience and earning power lost. This loss is made all the worse for occurring at the start of their careers, where the opportunity cost is the greatest, and it leaves them permanently behind in what they could have accomplished compared to their peers in past, real recoveries and their peers in future, real recoveries. This is nearly as devastating to our society and to our economy as the as the physically lost generations from war are to nations’ societies and economies.
It doesn’t look like it’s going to get any better, either. The only upside for that youth cohort is that they have time in their lives for (some) recovery. Older age cohorts have no such time.