Self-published authors, especially those writing romance and genre fiction, tend to focus on Amazon for their launches. Their books are often in Kindle Unlimited as well.

Kirsten Oliphant has good advice for authors on book launches if you're Amazon focused.

• A Tale of Two Launches: https://createifwriting.com/a-tale-of-two-book-launches/
• Big Launches Versus Low-Key Launches: https://createifwriting.com/big-book-launches-vs-low-key-book-launches/
• How to Stop Wasting Time and Money on Launches: https://createifwriting.com/how-to-stop-wasting-time-and-money-on-book-launches/
• How to Keep Consistent Book Sales: https://createifwriting.com/how-to-keep-consistent-book-sales/
• Getting onto the USA Today bestseller list: https://mailchi.mp/hotsheetpub/usa-today-bestseller#mctoc3