That's been a big part of the problem, this idea that there is some rate were we can have " employment and inflation normalize ". Bck in Niixon's time some moreon took the numbers from the 1960's and it ended up setting policy big-time:
It failed miserably (remember when Carter's 'stagflaion' was supposed to not have been able to happen?) and this is how inflation and employment eventually did work out over the long run:
Since then all kinds of eggheads have gotten rich 'explaining' how it really works but my take is there is no conncection between inflation and employment --and that the Fed does nothing for jobs.