>But cognitive behavioral therapy does not work by itself for ADHD.

But it does exactly that. There have been enough studies about this. CBT and medication combined improved faster, but CBT alone catches up in a few months. E.g. https://journals.sagepub.com/doi/abs/10.1177/108705471667119... or this study here: https://pubmed.ncbi.nlm.nih.gov/31280035/

>Stimulants are the gold standard treatment.

I'm not arguing that they don't help, but CBT also increases other metrics, e.g. self esteem, acceptance, self-efficacy, and so on.

ADHD is a spectrum, not on/off thing. Someone with milder symptoms may do okay without stimulants, and find help from therapy. Those with worse symptoms typically need the stimulants.