The narrative of "kids are depressed because of phones/screentime" is so enticing for adults because it lets us off the hook for our myriad failures: the environment, creating a socual safety net, gun violence, racism, sexism, hate directed at LGBTQIA people, etc, etc.
Youth are rational actors. They see the mess we are creating, and know they have no choice but to live in it.
And: adults have also failed to create a humane and ethical tech industry!
But sure - blame kids for phone use.