> For my taste, this standard macOS 26 Liquid Glass treatment muddies the boundary between UI and content way too much

Exactly this. Apple's marketing of Liquid Glass was about separating navigation from content so that content is more prominent, but in practice it's the exact opposite: animation, flashes, shadows, saturation. The navigation draws so much more attention than the content, especially so in macOS with that floating sidebar thing.

The Notes app, the Music app, and more. Why is the sidebar drawing so much attention? The increased roundness and padding also actively REDUCES the amount of content that is visible. People have compared iOS 26 with whatever iOS version was on the iPhone 5, and despite the iPhone 5 screen being only 4 inches (60% of the size of a regular iPhone today), it shows MORE content than today's iPhone with Liquid Glass.

It really feels like Apple has lost its head. How do people test this, compare this, and say "this is good, this improves the user experience"?