When the user starts my PWA from the iOS start screen (installed PWA) it accesses one instance of storage (IndexedDB, cookies, etc). When he starts the same PWA through Safari it accesses a different storage instance. It is very inconvenient, because from the user perspective he opens the same app, but he doesn't see the same data.
How can I make sure each PWA's data storage is updated when the other makes a change?
To make things more complicated, I can't rely on having an internet connection, so I can't sync my data with a server. And I can't force the user to only start the PWA from the start screen. And I can't use the new File System Access API, because it will annoy the user with file access prompts.