As far as I can tell all major iOS apps such as WhatsApp, Telegram and Spotify just enabled the compatibility Info.plist flag for Xcode 26 and went on with their life.
While indie devs sweated all summer trying to make Liquid Glass UI work in their apps, telling themselves they “need to be ready on day one”. The iOS dev echo chamber repeated this message to death.
I don’t think the general public cares one bit. Nobody gives a 5 star review because an app supports the new iOS UI. Nobody buys an app because of that.