long. BYU kept about 60K strong in LES and 15K strong at the MC all throughout Independence and the WCC for crying out loud. Now that we finally have access? Look out.
I expect BYU and its billionaire sponsors, donors, and fans to go all in on football just like they are in basketball. It's going to be a fun ride even if it takes a few years just as it did for Utah. Utah was absolute garbage vs P5s in 2012 and 2013. Even until last year Utah hadn't beaten a P5 team OOC in years. Hasn't won a bowl game since 2017...including two losses to Northwestern which you just listed as a program with major issues.
I have zero doubts BYU will be a force in the Big 12. Only a matter of time.