Well I don't know about worse than the opioid crisis, but maybe on a more subtle net harm basis because it's more prevalent (I think) than opioid addiction, especially in children.

Of course I saw parents ignore their children in the pre-smartphone era (which, when you think of it, is a mere 15 years ago). Smartphones and tablets and laptops just make it easier to do.

Also, not all of this is lack of interest in your kids. It is a need to escape from your life and its pressures generally. If you work at a crap job and stagger home exhausted to the demands of your kids and worries about bills you can't pay, THAT may be the more relevant cause than your phone. The phone is just a mechanism or catalyst, not a root cause.