In my opinion, social media is a bigger problem than smartphones in general. For me a smartphone is a just a tool that can be both incredibly useful but also very harmful.

With a bit of knowhow, you can neuter a smartphone so kids can't access social media, games, and other distracting mediums. No social media apps, no browser access, no YouTube, no games. But they can still access useful functions like calculators, the torch, phone calls and messages, etc. Android and iOS both have features allowing parents to do this.