If you still need to wrap a cross-platform web experience in a native container, I really begin to lose the plot. Once you are engaged with the iOS code signing monster, you might as well go all the way into the ecosystem.

To me, the web is the way around the app stores and codesign. I know how to visit HN on my iPhone despite there not being an official native app for it. It can work. The challenge is making it work in your particular case. Fear that the user wont know how to access the product seems to be a primary factor driving hyperbolic takes on how consumer apps must be built. Perhaps a bit of marketing budget (scan this QR code / visit this link) could eliminate a very expensive tech problem. Why fight visibility in the crowded App Store when there are countless other advertising channels you could pour your resources into?

> native code for the native notifications, GPS and healthkit / health connect.

Modern web can address everything here but the HealthKit item. You could consider handling this with a simple companion application that is exclusively about the collection and transfer of the data while respecting user privacy & consent procedures.