>Note: if the result is someone reporting having made a decision before brain activity is seen, my next question is going to be "How does that work?"

This is not how we figure conscious explanations are often(always?) post-hoc rationalizations.

See -

Split brain experiments - https://www.nature.com/articles/483260a

Experiments on Choice preferences -https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196841/