And the fact the Soviets practiced a scorched-earth policy as they retreated back to Leningrad

Scorched earth is more of a metaphor in this context, burning a field in winter is impractical. Rather it meant destroying livestock/infrastructure that couldn't be transported away from enemy lines, rails, power lines, mines, power plants, tractors, etc.

This probably didn't impact the famine inside the city as anything that could be transported into the city or further behind soviet lines was, and anything that couldn't would have been used by the nazis and certainly not given to the people in the city if it wasn't destroyed.

Weren’t there stories about residents resorting to eating dirt

This is common in other famines, it's probably accurate