I hate the fact that Amazon requires exclusivity for a KDP book to be in Kindle Unlimited. Exclusivity means the ebook version of a book can only be for sale in the Kindle store. Amazon doesn't care about the print version, but the ebook can only be a Kindle book. Amazon calls this status being in Kindle Select, and they sweeten the deal by allowing a limited number of promotions for Kindle Select books: the author can make the book free or on sale. Of course, you can lower the price of your Kindle book to 99¢ anytime you want to, but that's not the same as displaying it as "Regular price, $3.99, on sale for 99¢, YOU SAVE $3.00!" which is what the Kindle store buyers see with a Kindle promotion. It eevn shows how long the sale will last, which is a good impetus for a browser to click the buy button.
To date, I've never kept a book in Kindle Select for more than a single 90 day cycle. In the past, being able to make the book free for a few days was a great way to get some reviews, and reviews sell books. But once that first 90-day period was over, I always loaded the book on other platforms. I still plan to do that for Saronna's Gift, but not for another 90 days. I've signed on for another cycle because Kindle Unlimited has been pretty good to this book.
As I said in my earlier post, the Kindle Unlimited per-borrow fee paid to the author is running about half of what the royalty is for a #3.99 book. However, that doesn't mean you always make less money with Kindle Unlimited. That's only true if people who would have bought the book borrow it instead. As a new author, I think the borrowers I'm getting are people who might otherwise never have seen or bought my book. Ergo, I'm going to give it another 90 days and we'll see where we are then.
Hopefully, by then that book will have more than 6 reviews. Honestly, people, would it kill you to post a review? They make it really easy! There's a button right on the product page.