There's a very serious lack of literature on how to approach UX in DTN.
The Offline First movement was a step in the right direction, but it's not active these dasy and its primary focus was Progressive Web Apps (PWAs). However, the scenarios we're dealing with are more extreme than the ones PWAs were designed to support (e.g., the user may never connect to the Internet, the user may be under a lot of stress due to civil unrest).
I think we should try reaching out to the following communities and see if there's any opportunity to collaborate:
I've registered dtn.design in case we want to use it.
Current status
As of late 2023, we're requesting funding from the Open Technology Fund to do this in partnership with Neighbourhood.ie.