Likely not. Europe is in to open standards, interoperability, and things like this. Far more than the US.
Surveillance is an area where there are still plenty of politicians who try to sabotage (digital) freedoms.
Why not? Can you come up with examples? Are you worried that they would use automation to generate a new "API" per second, so consumers would need to play catch-up? Do you think that would hold in court, if/when this initiative has been legislated?
Well yes, if a messenger refuses to upgrade and consume a working API, it will not consume much. This law is not about forcing all messengers to interoperate with the infinite messengers out there. This law is about forcing those with capitalisation of ~7 billion to provide a sane endpoint.