Musk overtly uses his companies to retaliate against people who criticize him; he's not at all radically free speech in the sense of believing the owner of a company should not fully utilize the company to promote views that serve their interests and suppress others.
I still would be surprised if we saw Musk abusing his powers to make user-generated things disappear from Twitter.
Except the description of Musk as pro-radical-free-speech and the benefits supposed to result therefrom rely entirely on the definition (otherwise problematic, sure) that free speech means exactly that, and specifically that private actors will not use their own freedom to materially retaliate against you for your unwelcome speech.
Sure, you can maybe defend Musk being for “free speech” in exactly the sense that people claiming that Musk being for it will change Twitter say isn't “free speech”, and is the problem with the current approach at Twitter. But that...defeats the argument for Musk being a beneficial change.