This is what I use for authentication.

Advantages: free, free, free, with nearly unlimited cloud library space. The software supports multi-platform synchronization, and you won't find a product that covers more platforms than this. One-click export of highlighted content or annotations is much simpler than WeChat Reading. (Just try exporting annotations from 100 books in WeChat Reading to see how troublesome it is. Amazon has a lot of solutions.) It can't accurately display how many minutes you've read, but it offers reading goal rewards, such as weekly, monthly, yearly, and quarterly targets, and provides you with beautiful electronic bookmark images upon completion, which is much more thoughtful than the reading statistics in WeChat Reading. How is this achieved?