You were born with the only diagnostic tool that actually works!
All the so called diagnostic tools only provide information. Despite marketing hype, they don't provide reliable diagnosis. That depends on how you interpret the information provided. Certainly more information is better, so more than a basic code reader is a good investment. Just consider anything it tells you as signs and symptoms, not diagnosis.
I don't have specific tool advice, I just wanted to ensure you are not expecting more than any tool can deliver.