How do I make the icon in the taskbar the same as the desktop shortcut icon in windows 10?

The shortcut icon (that's the one on the desktop and also shown in the window when you open that window from that same shortcut) is something you can set yourself when you open the Properties panel for that shortcut.

However the icon in the Taskbar is the icon as set by the running application itself. Some applications use the shortcut icon for that. Others have another icon build-in for use in the Taskbar.
And that is something you don't have control over.

Ease of Access isn't a real program, but a plugin for the Control Panel application. So in this case it is the Control Panel application that provides its own icon in the Taskbar.