The only way to change the situation is to force those social networks to use their powers more responsibly. Europe’s GDPR law with its right to data portability is a step in the right direction, but it’s not enough. I believe we need more to regain our right to choose what services we use.

I wouldn't bet much on these laws, because it's the same EU that's drafting bills for lawful access to encrypted data - https://www.cyberscoop.com/encryption-europe-tutanota-protonmail-threema-tresorit/

The adoption of the encryption resolution in the European Union does not affect the landscape for encrypted services in Europe immediately, as the resolution is non-binding. But its adoption suggests a “shift in tone and puts pressure on the European Commission to propose anti-encryption legislation in the near future,” the encrypted email service provider ProtonMail has argued.

After portability, we need to discuss about interoperability, which in this case is the ability to contact people that are are using different chat applications than the one you are using. The way email and SMS already work.

I don't see a possibility for this in Signal, at least as long as Moxie is there pulling the strings and here are his views on federation - https://signal.org/blog/the-ecosystem-is-moving/

When someone recently asked me about federating an unrelated communication platform into the Signal network, I told them that I thought we’d be unlikely to ever federate with clients and servers we don’t control.

An open source infrastructure for a centralized network now provides almost the same level of control as federated protocols, without giving up the ability to adapt. If a centralized provider with an open source infrastructure ever makes horrible changes, those that disagree have the software they need to run their own alternative instead. It may not be as beautiful as federation, but at this point it seems that it will have to do.