Hello RP,
You can still transfer data using a PC app or even the Amazon website.
You can download Calibre ebook management software here.
How to transfer library Kindle Books via USB
On Amazon’s website, go to your “Manage Your Content and Devices” page.
Find the title in the “Content” list, then select .
Select Download & transfer via USB in the pop-up window.
Follow Amazon’s prompts to finish the transfer.