I think we have to reorient ourselves on what counts as social media. It's not just Facebook, Twitter, and Instagram. It's forums like Hacker News, it's comment sections on your favorite blogs you frequent. It's the products available on Etsy or a small creator's personal Shopify store.
Free speech isn't just about photos and text, it covers all forms of expression.
Nothing? I don't think it's that cut and dry. While there has been harm, no doubt, there has been a lot of positives too (maintaining connections, thoughtful conversations, etc).
Social media is such a big part of modern communications, that arguing against it is like arguing against telephone lines or the printing press. There's a lot to criticise the owner companies for, including how social media can harm people and infamously promote and accelerate genocide, such as Facebook is accused of having done in Myanmar. But the same accusations can be levied against any means of communication and publishing technology.
I see nothing wrong with that. Social media has done nothing but harm its users, and people that know its users (or: everybody)