Utah law only talks about who must yield. I use to believe that a person going strait had the right of way. Some of the confusion may come from the wording from different ways of entering the roadway. In Utah it says the following.
41-6a-903 Yield right-of-way -- Vehicle turning left -- Entering or crossing highway other than from another roadway -- Merging lanes. (1) The operator of a vehicle: (a) intending to turn to the left shall yield the right-of-way to any vehicle approaching from the opposite direction which is so close to the turning vehicle as to constitute an immediate hazard;
This doesn't actually apply to a stop sign because it says "other than a roadway". It also talks about "opposite direction" and not cross traffic.
The other part of the law that actually seems to apply is the following.
41-6a-902 Right-of-way -- Stop or yield signals -- Yield -- Collisions at intersections or junctions of roadways -- Evidence. (b) After having stopped at a stop sign, the operator of a vehicle shall yield the right-of-way to any vehicle in the intersection or approaching on another roadway so closely as to constitute an immediate hazard.
https://le.utah.gov/xcode/Title41/Chapter6A/C41-6a-P9_180001...