Learn Russian: Любой актёр должен выспаться к понедельнику. - Any actor must get enough sleep by Monday.

Together, they create the perfective verb выспаться, which carries the "saturation" meaning of the current lesson: to sleep until you are fully rested or satisfied. The combination of вы- and -ся often expresses fulfilling a physical or emotional need to its absolute limit.

The lesson title mentions that these saturation verbs take a Genitive object. Why isn't there one after выспаться?

While many saturation verbs (especially those with на-...-ся) take a Genitive object to specify what you had your fill of, verbs like выспаться or выплакаться (to cry oneself out) are exceptions. Because the base verb спать is strictly intransitive, it cannot take an object. The saturation applies entirely to the subject internally.

Why use к понедельнику to mean "by Monday"? Couldn't we just use до понедельника?

Using the preposition к + Dative (понедельнику) specifically marks a deadline: the actor must achieve this rested state by the time Monday arrives. If you used до + Genitive (до понедельника), it would mean "until Monday," which sounds like the actor is required to sleep continuously all weekend right up until Monday.

Why is выспаться in the perfective aspect here after должен?