Task Switcher moves to non-primary display on Mavericks-Catalina
I answered a similar question here - cmd-tab behavior on Mavericks with multiple displays

The Task Switcher does follow the Dock.  If the Dock is on screen 1, the Task Switcher will appear on screen 1.  If the Dock is on screen 3, the Task Switcher will appear on screen 3.  Etc.

To make your Dock appear on a screen you can use a couple of methods.

Method 1 - Move your mouse to the bottom of the desired display.  Don't stop once you reach the bottom of the display though, try to move it further down, as if you're pushing down on the bottom of the display with your cursor.  This action tells the Dock to move to this display.  This is temporary however, meaning the Dock will stay on this display until you perform this action on another display or reboot your Mac.

Method 2 - This will change the default starting point for your Dock.  In System Preferences > Displays > Arrangement you can drag the menu bar from one display to another in this windows display icons.  See the attached picture for reference.  This alters the default preference to always show the Dock on the desired display, the one you drag the menu bar to in this preference pane, when you boot and/or login to your user account.  You can still use method 1 to temporarily change the Dock's location but upon a reboot it will return to the display specified here.