3d text not working in z space

In 3D Space: 2D objects have no depth... no 3rd dimension... their appearance is an optical illusion.

You can "mix" 3D Text with 2D shapes (object) by using a "projection"... more commonly referred to as a Clone Layer.

Make a Clone of the 3D Text or Object and place the 2D objects in the same (3D) group *as the clone*. You can manipulate the Transforms of the 2D object to intersect the clone of the 3D object. [Edit: I actually recommend making the clone from the 3D Group *containing* the 3D Object! A direct clone of the 3D object may not look quite right.]

To make any changes in the perspective, manipulate the Transforms of the 3D Text/Object — *not* the Clone (the clone layer must always be "flat" in order for the "projection" to look correct — otherwise the look will be skewed.)

HTH

Sorry to say, but that is how it is... 3D text is rendered in layer order in relation to other elements in the Motion canvas. Same thing goes for USDZ models. They do not interact in 3D space with other Motion objects.

Sad.