He didn't need to come back to a college DC job since he already has an extensive coaching background. In fact, going to a college DC role probably didn't help if he wanted a pro DC job. He would have been better off staying in the pros.
I don't buy the "he doesn't like recruiting" hypothesis. He actually has a strong reputation as a recruiter. He came back to college knowing he would have to recruit. Considering the improvement in the talent on the defense, he is pretty darn good at recruiting for something you say he doesn't like.
Nobody really knows what his next career move might be. He might be perfectly content to be the DC at ND. Successful coaches are always going to get their names thrown out by the addled-brained lazy media who crank out meaningless lists to fill their "get published" quota.
I'm betting he stays at ND as long as he is happy or whatever he has in the back of his mind as his dream job pops open. Given the entire NIL/transfer rules and the evolution of college football, he is actually better off at a place like ND than being a head coach at a 2nd tier school that will be constantly battling to find NIL $ and keep guys from transferring. Recruiting, and football, would be far more complicated than it is at ND.