Yes, "Direct Access + Exit" IS the Home Shortcut, jcm2016.
To my knowledge, it is not possible to assign this function to a single button.
By the way, you can either press Direct Access first and then Exit, or you can press
and hold Direct Access while pressing Exit.
Basically I recommend that not too many displays are opened "one on top of the other". So it is best to always close the current display with Exit before opening something else. In this way, you normally only have to press Exit once or twice to show the home display.
Note: In many cases, parameter changes made are only saved (in the "System Setup") by closing the display via Exit (or touching the "X" symbol on models which have a touch screen).
Best regards,
Chris