It's undeniable that Utah has been more competitive in the PAC12, but this paragraph from Matt Brown's newsletter seems to indicate the Pac12 has just been worse, suggesting Utah isn't really better, their competition is just playing down to their level:

"In 2020, 2019 and 2018, the Big 12 posted a higher average Sagarin ranking than the Pac-12, with the four expansion teams, or by themselves (in 2017, the Pac-12's ranking was better). The same trend was true with F+, and I suspect it would be true if you used SP+, or Massey, or any number of opponent and/or pace adjusted metrics."