I don't think it's accurate to call the barrier between a streamer and their audience "the fourth wall". The fourth wall is a concept that exists in theater, and then more largely in fiction, where characters exist in a world where they do not know that they're characters in a story. And the fourth wall breaks when they realize that they are.

If "chat" breaks the fourth wall, then self-help books that use "you" are too, or news anchors addressing their viewers, or politicians saying "my fellow countrymen" in a broadcast address.