traced back to this article:

Note what Feldman said:

Kalani Sitake, BYU: One other intriguing name among the sitting head coaches a Pac-12 source mentioned who I thought could make some sense is BYU’s Sitake. The 45-year-old knows the league well from his days as an assistant at Utah and Oregon State. He has lots of recruiting ties on the West Coast and in Hawaii. His program is coming off a sensational 2020 season during which the Cougars went 11-1 and finished No. 11 in the country, and now the Cougars are off to a 2-0 start with wins over two Pac-12 schools (Arizona and No. 21 Utah). They face No. 19 ASU this weekend. If his team keeps winning, his stock will keep rising. His teams are physical, tough and smart. People in the business also love the guy. He comes across as extremely personable and likable. But he is coaching at his alma mater, and BYU is about to join the Big 12 and is in a much more favorable position in the sport than it was a month ago, so he might not be interested in leaving Provo.

Note, it's not even a USC source.  It's some random person (either a coach or an AD at some other school) in the P12 who said "Hey, Kalani Sitake might be an interesting idea for USC."  That's it.

From that point, the echo chamber took hold and people started repeating it back and forth.  Now local radio and media guys are reporting the same thing, with no other independent sources other than the Feldman article in the Athletic.

Until there's some actual of indication from USC that they're interested in Sitake, and some indication from Sitake that he might be interested in trying to coach at the University of Spoiled Children, then it's a big nothingburger.  It's speculation by someone not at USC that's been repeated often enough that it's taken as gospel truth.