The right approach here is definitely not to heat the entire board evenly during the actual rework phase. For socketless components like that, you want to manage thermal mass to prevent board damage, but the actual reflow needs highly focused heat. You are aiming for controlled localized heating over the component footprint and pads. The general rule is to use a preheater first. This warms the entire board up slowly, reducing thermal shock and minimizing the temperature jump needed later. It brings the surrounding components up to temperature so they act as a heat sink, which acutally helps protect the surrounding traces from sudden spikes.
Once the board is preheated, you switch to the hot air station. Position the nozzle directly over the memory chip footprint. You aren't trying to burn the chip; you are trying to get the solder to reach its reflow point reliably. Too much heat, too long, and you're guaranteed to damage the delicate copper lines. Keep an eye on the solder itself—it shold change phase and appear wet, not imediately evaporate or burn.
If you're worried about shorts because the area is so tight, use a lower airflow setting initially. A lower volume of super hot air is often safer than a high volume of moderate heat when working in microscopic detail. Since these memory chips are small and tightly packed, controlling the heat profile across the whole surface is more important than trying to blast the chip in one go. This method prevents uneven heating and reduces the risk of stress fractures on the board. Just make sure your hot air temperature matches the flux recommendations and doesn't exceed the chip's maximum specified limit, even if the manufacturer's suggested profile seems high. Even a small overexposure during the reflow event can be enugh to cause failure.