You’re getting at the distinction between the right to speak and the right to be heard.

There are tons of time-and-place limitations that make perfect sense. I can’t interrupt a city council meeting to give a speech about, well, anything not on the agenda.

And of course social media companies have no legal obligation to allow free speech at all, which is their own right to speech.

Core freedom of speech means the government cannot arrest you for what you say. Going beyond that to private companies being obligated to ensure your reach can be a moral argument but not a legal one.