Case Study
Amazon organic rank is driven primarily by sales velocity and conversion on your target keywords. External demand can feed that, but not by pointing ads at the listing. Build the demand off Amazon and let it arrive as branded search on top of well-structured Sponsored Products.
Pick one or two target keywords. Make sure the listing converts. Run Sponsored Products for on-Amazon velocity. Before reaching for external traffic, check whether the product is winning its conversion battle. A product stuck in organic rank is almost always losing on conversion rate, and the lever for that is usually price, not more traffic. Then hold the rank with steady performance.
How long until rank moves? A concentrated velocity burst can move a listing in days. Holding it depends on conversion.
Is this safe? Yes. You are driving real sales from real buyers, which is exactly what Amazon wants to reward.