You need to set the Z-zero of your 30 deg V bit at exactly the same spot as you did for the 2.5D model (Book). For the text, by selecting “Projecting toolpath onto 3D Model” the software will know where and how deep to cut your text.
Your Z zero should always be set from the same point. If you utilize a touch plate, do it for every bit change. If you utilize the surface of the material, use the same UN-CUT spot for every bit change.
The point to setting the Z zero is so that every time a bit is changed, the software knows where the zero is at, so it cuts the correct depth with each bit.
Just a little addition to the info already provided which is spot on
When I clamp/secure my workpiece to the CNC table I put a small cross in pen on a part of the material that I know will not be cut by any of the machining operations I am planning on doing. this way I have a reference point for setting my z zero for any tools that I need to use for that job
One other thing I have found is that the very corner of the material block can often be a little bit lower than the rest so try not to set your z zero position to close to the edge of the material