It's good that we can open many applications at once, without any hesitation, using our Mac. The bad thing is, more often than not, we will get distracted if we open more than one applications at the same time.
You can press Cmd-Opt-H to hide all other applications.
Or you can also hold modifier keys Cmd-Opt while clicking on the Dock icon.
Either one will result in showing only one application and hide others.
Personally for me, I seldom use Dock-clicking, usually I will just combine Cmd-Tab with Cmd-Opt-H. I am addicted to Mac keyboard shortcuts, I admit it!
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