I've been a happy user of a PWA doing local sync. That said, the data it needs to sync can fit in localStorage. Not affiliated in anyway, but the app is http:/

I've been a happy user of a PWA doing local sync. That said, the data it needs to sync can fit in localStorage. Not affiliated in anyway, but the app is http://projectionlab.com/ http://projectionlab.com/ and it allows you to choose between json import/export, localStorage sync, and server-based sync as desired. Since it has an easy to use import/export, sync with some other cloud provider on iOS is basically just a matter of "saving the file," since iOS lets you do background sync of authorized Files providers. Even though it's a web app, being able to download the page and then after run it entirely offline in a fresh browser window each time, built a lot of trust with me, to the point where I mostly run it with localStorage enabled and only occasionally check its online/offline behavior anymore.