PROBLEM
There are several means to isolate objects in the outliner, unfortunately you cannot hold alt and click on the eye icon to isolate one object/ collection. This is an industry standard for graphical, layer based applications. Using the right click menu or a double key hotkey will always be slower to activate.
SOLUTION
It would be an intuitive solution to add alt + Left mouse clicking the eye icon to both objects and collections to either isolate an object or a collection.