just ship a launcher that opens the webpage with the address bar disabled :p
https://www.macrumors.com/how-to/add-a-web-link-to-home-scre...
When you tap on the icon on the home screen, it'll open up in Safari without any browser chrome visible.
I hate to say it, but I’d probably pay apple a cut if they’d let me distribute PWAs through their App Store without going through the trouble of building a lame native wrapper.