Apple has since commented on this: Update on apps distributed in the European Union - Support - Apple Developer
Apple has since commented on this:
Why don't users in the EU have access to Home Screen web apps?
To comply with the Digital Markets Act, Apple has done an enormous amount of engineering work to add new functionality and capabilities for developers and users in the European Union — including more than 600 new APIs and a wide range of developer tools.
The iOS system has traditionally provided support for Home Screen web apps by building directly on WebKit and its security architecture. That integration means Home Screen web apps are managed to align with the security and privacy model for native apps on iOS, including isolation of storage and enforcement of system prompts to access privacy impacting capabilities on a per-site basis.
Without this type of isolation and enforcement, malicious web apps could read data from other web apps and recapture their permissions to gain access to a user’s camera, microphone or location without a user’s consent. Browsers also could install web apps on the system without a user’s awareness and consent. Addressing the complex security and privacy concerns associated with web apps using alternative browser engines would require building an entirely new integration architecture that does not currently exist in iOS and was not practical to undertake given the other demands of the DMA and the very low user adoption of Home Screen web apps. And so, to comply with the DMA’s requirements, we had to remove the Home Screen web apps feature in the EU.
EU users will be able to continue accessing websites directly from their Home Screen through a bookmark with minimal impact to their functionality. We expect this change to affect a small number of users. Still, we regret any impact this change — that was made as part of the work to comply with the DMA — may have on developers of Home Screen web apps and our users.
Apple has since commented on this:
Update on apps distributed in the European Union - Support - Apple Developer