Looks like a hot-air rework setup. I've swapped chips by hand that way, once the solder is molten they'll fall right off the board. The hard part is lifting them away without accidentally dislodging anything else.

exactly, + we preheat the board before to let the trapped air out. would love to hear more about your experience doing this by hand and where you see automations for this applicable

At 0:16 it looks like they're heating the board from below?

thats right! thats to let the trapped air out and preheat before a manipulator heats the target up further and unsolders it.