I have a notebook running Windows 10 version 1803 (won't update to 1903, but that is another story) that I use either mobile, or at my desk. When at my desk, I run it with the lid closed, and 3 external monitors connected. Previously I used the click-n-drag method to relocate the taskbar to my default (middle) monitor.
Before you declare this a duplicate question, all of the other answers that I can find state that you can click-n-drag, and it worked - until about 3 weeks ago.
I can click-n-drag the other two occurrences of the taskbar around their respective monitors, but not between monitors. I cannot even drag the main taskbar around it's own monitor.
"Lock all taskbars" is not checked. I have even tried moving the taskbar with it checked, but as expected, that prevents any movement of the taskbars on any of the three monitors.
When I choose to Identify the monitors in Display Settings, the main taskbar is displaying on monitor 2. I'd currently be happy if the best I could achieve to have it fixed on monitor 1.
I have my left and right monitors orientated portrait, and my middle landscape, hence the offset levels of the taskbars in the linked image.