Some people love Apple’s new Liquid Glass interface. Most of them work at Apple.
Jokes aside, the springy, heavily animated, and relatively transparent user interface–included with the latest “26” operating systems for Mac, iPhone, iPad, and all other Apple devices—is divisive. Many users like it, but designers and accessibility advocates criticize it for sacrificing clarity and readability on the altar of flashiness. People with older devices find the graphically intensive design is slowing everything down. And others just find the morphing transparent blobs to be kinda … ugly.
Whatever camp you're in, there is no way to roll back the user interface entirely to the way things used to be. But there are some settings you can tweak to de-Glass things, increase the readability of onscreen text, and speed up your hardware if the animations are bogging down your device.
Reduce Transparency
Reduce the transparency of interface elements in the macOS settings. Courtesy of Justin Pot
Hidden in the Accessibility settings of your Apple device is a toggle to Reduce Transparency. Flipping this toggle will make windows and other interface elements less see-through.
On a Mac you need to open System Settings, click Accessibility in the left-side panel, then click Display. You'll see the toggle for reducing transparency. Toggle this and you'll notice right away that the menu bar is whole again. As you use the operating system, you'll notice that most for the formerly glassy see-through elements are now mostly solid.