This probably has already been discussed ad nauseum on the board, but I pulled this together for myself, so here it goes.

The official policy is here: https://big12sports.com/documents/2024/9/5/Big_12_Football_2024_Tiebreaker_Policy.pdf

Here is a good scenario generator: https://bball.notnothing.net/big12.php?sport=fb

If Iowa St wins out, then BYU can lose any one game and is still very likely (perhaps guaranteed?) to be in the championship game, because BYU has major tiebreaker advantages over Colorado.

If Iowa St loses to Kansas St, then BYU is in massive trouble if it loses to Utah or Kansas. It has major tiebreak disadvantages in that scenario. If BYU only loses to Houston, it could also be in trouble in certain scenarios. If BYU loses to Arizona St, then BYU is still in great shape.

Short answer: Don't lose, especially to Utah. No pressure.