Kindle Unlimited isn’t doing anything new. Subscription services originated outside of Amazon, leading the way for readers and authors to find a new way to interact. But KU did tap into the largest market of ebook readers.
That has caused some difficulty for indie authors…and likely for traditionally published authors, as well. Generally payments are down, even if reading rates are the same or stronger.
What this means is that it is time once again to shift the way you produce and market your books. Consider having only some of them available through Kindle and sell the rest of your ebooks on a different site. This could work especially well if you allow print versions of all your books to remain on Amazon.
Also try moving the price points for ebooks you leave on Amazon to a higher point. This could change the borrow rate by broadcasting to readers that your work is worth more. Higher valuation results in greater respect, and more consumer demand.
Finally, always have a direct pathway for sales. Use Gumroad to sell ebooks directly to readers at a discounted price. You’ll receive more money per sale even at $0.99 than Amazon’s standard 35% royalty at that price and you’ll potentially reach more readers.