I think this is a good highlight of why context and reality checks are incredibly important when doing work like this. At first glance, it might look like 55% is a really good result, but in the previous year, a flat buy every day strategy would've been right 56.7% of the time.
55% means basically nothing in this context if even money. Long 45% to 55% is most likely completely random because it is symmetric with shorting 45% to 55%
Exactly what you would expect from a language model making random stock picks.
https://www.crestmontresearch.com/docs/Stock-Yo-Yo.pdf