After the week is done to figure that stuff out - no one really cares about you anymore. There is likewise a tacit assumption that you won’t deliver anything again (why would you?). As such it’s usually best to let someone out the door after a week.
Typically when I give notice, I simply state that the employer can do whatever over the next 2 weeks. 70% of the time, when given the choice, they will decide on a fast transition of 1 week. There hardly is anything to do the second week.