The fact that it took the entire daylight portion of the day for the Israelites to plunder the Egyptians and leave Egypt is not hard to understand when you consider that the group likely numbered over 3+ million (below is what we know along with a few assumptions).
600,000 (footmen, Num. 11:21)
3,000,000 (assuming wife and 4 children per footman)
50,000 (assuming number of mixed multitude)
If anything, this number is probably conservative. It’s also important to remember that this exodus included children and the elderly along with their livestock and flocks. This is larger than the city of Los Angeles. How long would it logistically require, even if they made preparation the night before, for the population of a Los Angeles to evacuate the city? This would require more than 2-3 hours, it would take the entire day and then some for a group of this size to evacuate.