I have Moon+ Pro on both tablet and phone now. I have the shelf loaded. But I still don't see the setting to sync bookmarks across devices.
I don't believe Moon+ Pro can sync anything other than the current location in a book. The only way provided to move highlights, notes and bookmarks between devices is to export settings on one device and import the export save file on the second device. See their FAQ
I use Moon+ Pro for hard-to-read epub books because it easily handles large or poorly structured epubs that other readers choke on, but my regular epub reader on Android is Bookari Premium
, which has better navigation, bookmarking and annotation capabilities. Bookari is also my pdf reader of choice on Android.
Bookari has subscription plans that allow users to sync between multiple devices through their own servers. A free account will only sync current location in a book between two devices, but their paid plans
, which start at $10/year, allow you to sync everything between multiple devices, export notes, and more.
Some years ago, when Bookari was called Mantano Reader, I tried their online service briefly but it didn't offer enough at the time that I wanted to subscribe. It looks like they have greatly improved it since then, and I'm considering trying it again.
As an aside, the method used by Moon+ Pro for loading epubs in chunks is great for reading on a phone because it allows for continuous scrolling through a chapter, but less useful on a tablet, where I do most of my reading. It also makes it hard to find your place in a book if you switch devices or readers, because it does not display epub page numbers (NOT the same as print book page numbers).