Oh wow. I'd assumed, in earlier discussions about this, that Apple'd just keep forcing Safari-only for PWA installation and use.

Does the rule not allow that? If so... yeah, as a user deep in their ecosystem and once-developer for the platform, hard agree on this. Whatever their other motivations (and Apple are masters at arranging things so that their interests happen to coincide with legitimate concerns about UX) the user-facing issues expressed are worth worrying about.