Would invest into it’s campus and infrastructure (faculty and practice).
I agree with nearly all you point out. To transform into a better university to match BYU’s UG level, much would have to change - but I believe it could with investment.
As someone who has been in academics for 20+ years, having graduated from and taught at tier one universities, I wouldn’t take a job at BYUI at this moment. Mostly for the reasons you pointed out (pay, workload, treatment of faculty and work environment....).
With that said, if there was a movement to attempt to strengthen BYUI and transform it into a stronger university, I would be intrigued and could be persuaded to come help build something unique and strong. There would have to be a change in philosophy and changes in directions. Salaries would have to increase and plans would have to be lined out where future faculty could feel like something special was emerging and evolving. It COULD happen, but likely will not - at least not anytime soon. Remember, the “I” still has an out of date Honor Code (no shorts...really!?!?). Things often times change very slowly in that campus.