How to unlock Z axis rotation?

I have been struggling with it for several days, I tried world, actor, local rotation.
Why can’t I rotate an object on the Z axis, the Z axis is always locked vertically.

From your video it looks like the object is rotating in all axes.

Rotators are devious and deceitful. Especially if you break them down and manipulate their constituents. The don’t like that, and rarely will you get the result you want.

Here’s what I came up with and it works fine:

Just AddLocalRotation before saving the target rotation. Since you start the timeline right away, it will set the initial rotation in the same frame, so you won’t be able to see the effect of AddLocalRotation and it seems just fine.

TRI99ER_
ZZZ, YYY, XXX this is key input Z, Y, X
Look at 26 second,
x axis is up i click ZZZ and this thing rotate in X axis, if i change to y pointing up pressing Z will rotate the Y axis, if i bring the Z axis up, pressing Z will rotate the Z axis.
only Z axis stay always UP,