I made an HTML5 Offline app years ago, and with much effort got it to do some impressive things, in a cross-platform and update-able way. But it was especially difficult on Safari, and seemed like Apple had intentionally regressed on some standards, for whatever reason. Android seemed to support the standards better. Desktop browsers worked well, but we were mainly interested in a particular tablet, and secondarily in other handhelds.

I later made a tricky iOS-specific app for a different purpose with SwiftUI, and it was successful after much effort, but the whole Apple App Store process and distribution was so much headache. The problems were Apple's heavy-handed authoritarianism, the slow iteration with reviews, and surprisingly inconsistent quality/correctness of the developer account site and TestFlight.

I'm not a huge fan of Web technologies lately, but at least they can mean being relatively free of the app store tyrants. And maybe there's a way to hold the device platform vendors accountable for supporting open standards properly. It might have to be with legislation or government purchasing pressure (since we techies collectively have dropped the ball on that accountability, such as with adoption and professionalism).