If your real goal is just to have your own unique app on your iPhone ( my assumption as you are talking about using third party apps to view your page offline)
Then I would suggest you build you own iOS app.
This for what it looks like in your case is very easily done.
@Djon has posted a very quick and nice tutorial on how to do this using some SwiftUI code I created a while back.
If you follow the instructions you should be able to create your own app and then load it on to your device.