BYU is deeper there than they have been for years. Losing Takitaki and C. Kaufusi is a big deal, but D. Kaufusi, I. Kaufusi, and J Kaufusi are all there and looking pretty good. Khyiris Tonga has been excellent on the D-line, and has trimmed some wait so should be even better.

There's a lot more than that. I expect this defense to be better than 2018, where they were ranked 24 (Utah was ranked 17, btw). It sounds like you're not really informed about BYU.