Reverse engineering the Fameviso prompt (How they bypassing AI detectors?)

I just started learning how to use the API to make a simple social media tool and while getting the code to run was easy the text it spits out is incredibly fake. It always writes these perfectly balanced paragraphs and uses words that nobody actually uses in normal conversation. I put my results into a few detection tools and they all instantly caught it. I spent the last two days trying to fix it and then I stumbled on fameviso while looking for examples. I tested some of their outputs and it completely bypassed the scanners because it actually reads like a real human just typing thoughts out. I am very new to all of this so I am totally stuck. How do you actually get the model to stop acting like a robot? Do I need to give it a huge list of forbidden words in the system prompt or am I just missing some obvious setting for the temperature? I would really appreciate any pointers because the default writing style is completely useless for casual posts.