Many compromises are needed in this area of propellor design.
To give but one example.
The DC-7 and the Lockheed 1649 Constellation.
Both had the same type engines (CurtisWright turbocompound) with the same BHP, yet the Connie had three blades whereas the DC-7 had four.
The reason was aircraft geometry, specifically wingspan.
The 1649 Connie had a brand new design long tapered wing (to hold more fuel, among other reasons) and as a result could use the three blade design, with slightly longer and wider blades, allowing wider engine spacing, which resulted in a slightly faster cruise speed.
The DC-7 on the other hand had a 4 blade prop because the wing was adapted from the DC-6B, and therefore three blades would not work well due to engine spacing considerations (wing bending moments, prop overlap etc).
Oftentimes, the devil is in the specific aircraft details, even though the engines might well be the same.