Hi Stefano. I am writing to you to share my experience and follow a possible development. I wanted to squeeze this tool to use it actively on an ongoing project, setting the xyz coordinates, as you say. It is not possible to do this and I think it will not be possible for some time. I have tried other systems even outside of VCS and I have to confirm that it is a world where there are those who can do it with millimeter precision, but they are extremely expensive services.
From here I realized that VCS in AR must be used to show a kitchen furniture, a set of desks in a studio. Or a whole project but in VR. My heavy model can't handle it and I never have time to find the right balance. As for the navigation in Unity, however, I have to tell you that I found myself quite well on the desktop, but on mobile I don't remember negative experiences. But maybe I have to check if the same system is active. In short, I remember a positive general experience.
In my opinion a very nice thing would be to be able to insert the sheet layers in comparison with the sectioned model with section volume. They have done great work lately but it must be admitted that from a professional point of view we are far from other BimX cone applications. Hoping for a precise xyz alignment to be able to for example see the plants on the ground on an existing structure is too much. But looking for the way to be able to integrate 2D views with 3D views might be the right direction to implement project understanding and division.