PWA local storage on iPad

I wrote a PWA that needs to collect data offline, save to local storage on a set of iPads, then eventually upload that data to a server. It works great on Safari on the iPads, but I’d like it to run in kiosk/full screen without the browser tabs, address bar, etc. (It’s for co-workers to take to conferences and gather leads).

I can get the kiosk appearance & behavior by visiting the page and clicking ‘Add to Home Screen’ and it looks great. However when you open it, iOS apparently creates a contained new instance of Safari with its own local storage that gets wiped out as soon as you close the app… big risk of data loss.

Anyone have ideas on how I could A) prevent the local store from getting deleted when the app closes or B) run the page in a regular browser in full-screen mode?

I should note this is a minor project, I’d rather not bundle into a full-blown app unless that’s the only option