If I understand correctly, it has nothing to do with a UCS. You can see the XYZ cursor position in the status line. If you don't see coordinates down there, pick on the "hamburger" icon at far lower right, and check Coordinates at the top to turn on that display. It can display in four ways -- see Help about the >COORDS System Variable<. If you have Dynamic Input on, that seems to still show only distance and angle, but the status line Coordinates display can show what you want [it sounds like you want COORDS = 1]. You can pick in that Coordinates display itself to change the COORDS setting. But if you do that with no command active, it merely toggles between 0 and 2. Do it in mid-command [e.g. while drawing a Line, or Moving something], and it cycles through 0 / 1 / 2.

Watch changes in the Coordinates display at the bottom -- the manner of display up in the drawing area with dynamic input on does not change. This is during a Line command. At first, the Coordinates display is what I think you want with COORDS = 1 [continuously updating coordinates with cursor movement]. After the first Line, I picked in the display to go to COORDS = 0 [fixed display until I pick somewhere], then after a couple more, again to go to COORDS = 2 [distance and angle], then after another couple, again to go back to COORDS = 1.
Kent Cooper, AIA