Elon Musk has invented nothing, so let's not give him that type of credit for Neuralink. There's also no clear evidence that he's a stutterer versus just a neurodivergent speaker. In any case, even if a form of that technology eventually evolved into something that can manipulate a portion of the brain and/or other systems to circumvent the root cause of stuttering (which is unlikely to be the same in every person anyway), that would likely be many decades away.