If the oil is overfilled to the point where the rotating crankshaft comes in contact with oil, the crankshaft will aeriate the oil as it rotates. When oil is aeriated with air the oil pump can no longer pump oil throughout the engine so the engine is starved of oil and the oil pressure falls off.
From what you’re describing, it appears the oil was overfilled to the point that this aeriation did take place, and the engine damage was caused from overfilling the oil.
Tester