Beware: don’t genre-stuff
Back in the day, a decade ago, you could make a lot of money on Google AdSense by “keyword stuffing”, adding random keywords to website pages so that they came up for searches in Google.
Searchers clicked through to pages, couldn’t find what they wanted, and clicked on AdSense advertising. The website owner made money. Similar tactics will get you banned today. :-)
You want your ebooks to be discoverable on Amazon, but please don’t be tempted to “genre-stuff”. That is, don’t add random things to your book descriptions so that you come up in searches for several genres.