LOS ANGELES—For Meta Platforms, which made $60 billion in profit last year, getting hit with legal damages of a few million dollars is ordinarily a nonevent. But back-to-back jury verdicts holding the company liable for harms to young people could open the way to a flood of litigation that could force it—and other social-media giants—to make significant changes to the way they design and deliver their products. That is the view of some legal experts, but also the stated position of Meta itself, which argued heading into the trials in California and New Mexico that for juries to endorse the…