I'm not advocating an end to global platforms. And I don't think the democratic oversight should come from the US government. The end goal should be a website like Wikipedia -- non-profit, maintained and perhaps even funded by users.
In fact, I think a lot of the fragmentation of the internet you see abroad is a reaction against the powerlessness of users and governments against the unassailable power of these corporations. Maybe, if we are able to give users some degree of control over the design and policies of these platforms, we might be able to preserve the global internet. Some of that fragmentation -- as you see in the OP article -- is simply a result of governmental authoritarianism, which is a problem either way.
I think the first step would be to re-align some economic incentives by creating digital rights laws. GDPR is a good first step. So establishing something similar in the US. This itself is a hugely complicated step that could go very wrong, and due to the corrupt nature of US politics and the desire for large tech companies for regulatory capture, the potential pitfalls are many.
Then, if we manage to get that right, I think we need to find a way to create legislation that requires these platforms to give their users control regarding how content is presented to them -- essentially, the ability to control their feeds.
I don't know how we would manage to transition these companies to a true non-profit model. As long as they remain for-profit, they will fight and subvert these efforts every step of the way, even after they became law.
However, I think we are increasingly seeing how dangerous and unsustainable the current model is. Perhaps the best way to accelerate data rights is accelerationism -- making the exploits and faults in these platforms as visible as possible by "hacking" them.