-we have option to full screen Maya by unchecking show title bar
save the preferences then relaunch Maya
-I tried it with Maya 2020.1 the task bar still shows-up but no need to relaunch Maya
-since Maya needs relaunch to get full screen we can't assign a keyboard shortcut to this option .
I have certainly removed the title bar. The screen is clearer, that's for sure.
However, it does not go to full screen.
(It means that the display area of the application window is extended to the taskbar.)
Is this a specification?
Here are some examples of other software. (Blender)
before
The display area of the application has expanded to the task bar.
show title bar off
I'm sorry. I was wrong.
The moment I unchecked the show title bar as you said, the title bar just disappeared.
But when I started Maya again, the application window became a full-screen Maya window (toggle window).
If you usually close the window from the title bar,
Use Alt+space to select the bottom of the screen or Alt+F4.