I'm at a bit of a loss as to what to say.
Your model is all loose geometry, the only component is the scale figure that shows as a nested instance.
Once Solid inspector has fixed the issues it can there are still holes and overlaps that you need to address manually.
To get a volume the object needs to be a solid.
GIF 25-01-2024 8-39-54 PM.gif
Once fixed and grouped it does show a volume.

https://i.imgur.com/mRSSVkh.png

You don't need any special extensions or plugins to do this. Just enter the coordinates in the Measurements window. For relative coordinates use the form <x,y,z> and for absolute coordinates use the form [x,y,z]. I used relative coordinates in this example. And then the Text tool will show the coordinates when the leader is anchored to a point in the model.

click on the picture