The effects of transparency from the system macOS They are beautiful and attractive, but often they distract us, and in addition, any Graphic effect / visual Consume extra resources. Memory and CPU.
It's about transparency sidebarand a toolbarto the Finder, a Dock and Bar menu. If Dock and Menu Bar, transparency does not bother us, when we scroll into a folder with many files, running them in transparency on the toolbar becomes upset.

Fortunately, we should not be experts in maccos if we want to deactivate this transparency effect.

How can we disable the transparency effect in Finder, Dock and Menu Bar on Macos

open “System Preferences“, then we go to “Accessibility“.

In “Accessibility” We tick the option “Reduce Transparency“.

Once this option is checked, All the transparency effects on macos were disabled.

Also from the accessibility settings you have options of Reversal colors or to pass the display into BLACK & WHITE (I don't know why anyone would do these things), contrast change )we do not recommend), deactivating the effects of motion (when we close / open a folder or application) and the possibility of raising mouse cursor.