You can try to make the AI come out with realistic content, but ultimately, the thing to do is focus on making your writing as human-like as possible. This can be done by incorporating natural variations in the supposed tone as well as the sentence structure and diction.
Basically, you would start with whatever it is that the AI concocts. Something reliable and of high quality, and then inject personal anecdotes, emotional nuance, and/or subjective observations to add that human touch. Also, use a mix of lengthy and short sentences, including idiomatic expressions wherever appropriate, and then edit out repetitive or overly formal or robotic phrasing.
However, if you, for whatever reason, do not want to do too much work yourself (maybe you have to edit posts in large volumes, for example), then you can also just get the AI to reword it for you a few times. They tend to utilise specific narrative POVs in writing (usually 3rd person), so changing the perspective could go a long way. Ask it to use a mix of formal and informal/personal speech and see what happens. You can also get it to write in the style of someone whose writing you like so long as they have an extensive list of works online.