Safari 26 brings websites closer to app-like experiences on your iPhone and...

https://bizzmarkblog.com/why-does-my-ipad-web-app-feel-different-from-the-same-site-in-safari-tabs/

Safari 26 brings websites closer to app-like experiences on your iPhone and iPad. When you add a site to your Home Screen, it now launches without the usual browser bars and controls, giving you a cleaner view