A story rarely arrives as a plot. It arrives as a question that refuses to leave, and the work of a writer is to follow it far enough that a reader can feel the weight of the answer.
Research is a series of detours taken on purpose. A footnote leads to a paper, a paper leads to a name, a name leads to a place that was never in the plan. Some weeks the reading feels endless and the page stays blank. That is not failure, it is the part where the material is still being sorted into what belongs and what only sounds good.
Verification is part of the craft. Names, distances, procedures, and dates have to hold up, because a reader who finds one wrong detail stops trusting everything else. Accuracy is also respect: the people and places behind a story deserve to be described correctly.
Between the notes and the first draft there is a stretch of discomfort where the book is neither one thing nor the other. The only way through is to start writing badly, on purpose, and let the sentence teach the next one. That is where the story finally stops being research and becomes a thriller.