Think about this… You don’t check torque on engine connecting rod cap bolts every year. If connecting rod bolts are properly torqued and secured, they remain unchanged for complete engine run. The design torque stretches the bolt so that all forces applied during operation remain below the stretched force and the bolt then sees no cyclic loads.
Same design philosophy applies for cylinder head bolts and bolts that hold crankcase halves together. All are pre-stretched above cyclic loads.
Prop flange bolts are same thing. It would be disastrous if prop bolts were subjected to cyclic loads. The design torque puts the bolts in sufficient tension that cyclic loads are always less than the force applied and held by the torque. Wood props are a deferent story. Alloy and geometry used for aluminum hub, aluminum spinner back plate, steel crankshaft flange, bolt grade and fit, are all accounted for by the designer when specifying torque. Computer models and real-world testing verify safety margin for the torque value.