progressive internet apps – iOS PWA: The right way to (re-)allow pull to refresh?

There are a number of questions on Stack Overflow asking how you can disable pull-to-refresh, whether or not when their web-apps are visited within the native iOS Safari browser, or as a standalone (Homescreen) utility.

My query is how you can allow it. Someway with my app, the pull-to-refresh performance works effectively with Safari, however not when the app is open as a standalone Homescreen utility.

I might like so as to add any related data wanted, besides that I do not know what to specify. This is the abbreviated manifest.json:

{
  "title": "x",
  "short_name": "x",
  "description": "x",
  "dir": "auto",
  "id": "https://www.myapp.io/",
  "lang": "en-US",
  "show": "standalone"
}