How do you quickly align one object to another along only one axis? I know about Object > Transform > Align Objects, but this is too slow. Even if you make a keyboard shortcut to Align Objects, you still must use the mouse to click on the desired X, Y, Z axis.

I know about the Pivot Point Align method where you scale to 0. In Blender 2.8, this seems to be disabled. Alt + , does nothing and the Pivot Point Align button no longer appears in Blender. Even if this mode were still available, changing modes and scaling to 0 each time you need to quickly center something would be way to slow.

Surely this is such a common operation in 3D modeling that is done all the time. How is it done?
Begin with the solution you already know, which is to go to Object > Transform > Align Objects, except that instead of left-clicking to choose Align Objects, right-click on it instead, and choose either to create a shortcut, or to add it to your Quick Favorites menu (which will then make it accessible with the 'q' key). The Quick Favorites option is very fast and easy to use, provided you only have one or two items in it at a time (you can have more, but I don't recommend it).