The phrase "stumbles on" refers to the act of accidentally discovering something. There are several synonyms for this phrase, including "chances upon," "encounters," "discovers," "finds," "stumbles upon," and "comes across." These words all convey the idea of finding something unexpected or surprising without actively seeking it out. Whether stumbling on a new job opportunity, chance meeting an old friend, or discovering a hidden gem, the word choice can convey the level of intentionality of the discovery. Regardless of the phrasing, it can often signify a turning point or serendipitous moment in one's life.