Someday you will update to integrate with the cloud?
Some kind of API or ready-made with the most widely used databases and server systems.

inconvenient to keep everything on one device

and besides, having access to the data on the server, you can visualize it for yourself as convenient

 To date, the use of the cloud is not considered, except as part of an evolution towards shared writing, which poses many design problems.
(translated by https://www.deepl.com/translator)

If you aren't talking about two (or more) authors working on the same project, DropBox or SyncThing or any of a dozen or so others handle file syncing quite competently. There's no need for oStorybook to do it too.

If you are, then you have bigger problems that oStorybook is not currently designed to deal with - and it would likely require a complete redesign. I'd suggest that either you find a story-writing program that resides on an application server in the cloud and keeps the *only* official copy of your project in the cloud *all* the time, and you access via a (possibly specialized) web browser; or you use a story-writing program that keeps the project in many separate files using directory structure and the like for organization, and use something like GitHub as your cloud.

I couldn't have said it better.