There is OpenHFT, Hummingbot (for crypto), and probably a few others, and there will only be more of such open source software for retail traders. So why aren't you using them?
Though there is plenty of software NOT available to retail traders and not making big money or sometimes losing money, just like Interactive Brokers' Timber Hill division that was losing money and then sold. HFT shop Trading Machines is well known as well. So what can their software do for or to retail traders, when it couldn't do anything in the hands of experts?
And what retail traders can do with software that requires $million dollar infrastructure and a team of mathematicians, physicists and technologists, who still lose money and close the door?
The ones that make money, like Citadel, buy order flow from brokers and may need retail traders to make money.
While the ones in business of actual trading are called hedge funds and don't need HFT.
And here is someone who is suing "AI" for losing $20M of his money:
https://www.fa-mag.com/news/who-to-sue-when-a-robot-loses-your-fortune-44695.html