Hi,
From the doc at:
https://photonstorm.github.io/phaser3-docs/Phaser.Input.Pointer.html#worldX__anchor
worldX :number
The x position of this Pointer, translated into the coordinate space of the most recent Camera it interacted with.
If you wish to use this value outside of an input event handler then you should update it first by calling the Pointer.updateWorldPoint method.
Try to update the pointer in the update function with (not tested):
update(time, delta) {
this.input.mousePointer.updateWorldPoint()
...