One can find numerous synonyms for the phrase "descend into." For instance, a person descends into a state of anxiety, worry, or depression, they sink into a state of despondence, collapse into desolation, or plummet into a pit of despair. Similarly, if an individual descends into a place, they can delve in, go underground, sink below, or submerge to the ground level. Moreover, if something descends from a higher position to a lower one, it can drop, decline, plummet, or tumble down. These synonyms enable us to diversify our language use while also conveying the same meaning.