The challenge with Amazon is that impressions are limited to the search volume of your keywords (unlike Facebook where you can scale to your heart’s content.)
With paid Amazon, you can increase your bids and ensure you're top of search, but if your listing is garbage, or you have a bad star rating and you're sitting next to competitors with 1000 five star reviews, you're not going to get clicks and you're not going to get sales.
One option is targeting smaller, less competitive keywords. Another is to go off Amazon and get creative running Facebook to Amazon campaigns (read about the FB | AMZ Bridge here).
The one source of leverage you do have is your product image. Amazon guidelines say it has to be your product on a white background. However, unless your product is square it’s not going to take up much real estate and there'll be a lot of dead space. One option is to create product packaging around the actual product that takes up the entire image to get eyeballs on listings 👀 sing the extra space to showcase some top product benefits.
More clicks, more spend, more sales 📈 (providing your listing CVR is dialed)