One thing that has emerged recently is the use of AI humanisers. These tools are aimed at making the content sound as if a human and not an AI wrote it. These tools are a strange proposition, as they take the content and then use AI to rewrite it as if a human has written it or to bypass AI detectors.
But circling back to the question above, Google doesn't have a preference for who (or what) wrote the content initially. So, these tools do not seem to offer much value at this time. Obviously, AI is a rapidly changing area of SEO, and things may change in the future. But in short, if you genuinely want to humanise your AI content, then get more involved in the content creation process yourself.
A quick tip is if you are sure you want the content to sound more human, then you can even achieve a similar effect by asking your AI to rewrite the content as if you were a human. We don't do this, as we feel just getting AI to churn out content, without any human intervention, is most certainly going to lead you to fall short of E-E-A-T guidelines.