Embodied Carbon - Standardization

i am a civil engineering student who is trying to develop a Embodied Carbon Calculator for the engineers in Australia (my Thesis project), however, researching i found many peer-reviewed articles but with a big variance between the emissions because it depend which methodology was applied in order to manufacturer that material, transportation, etc.
At the moment, i understand that is necessary to create the material EPD (Environmental Product Declaration) based on the product LCA ( Life Cycle Assessment), in order to provide a standardised and transparent way of communicating a range of environmental impacts of some product, such as EPD - Australasia does.

The Australian Government still needs to determine an Embodied Carbon Protocol, for further standardisation on LCA in order to create a robust database and for a more comprehensive presentation of the results. The Australian Institute of Architects has already started writing a new Australian Standard Framework for measuring OC (Operational Carbon) and EC (Embodied Carbon), and they want to incorporate it into Australia’s building code until 2025.

Am i correct? So in order to have an accurate carbon calculator tool, the Australian Government should implement an standardization of how the materials must be produced to achieve an standard value for each type of material? Or the Government should provide a standard carbon emission value for each Australian State, or the same standard value for the whole country? Or the companies must provide the EPD of each product? so the engineers can calculate the total embodied carbon of the project.

Any information about will be really helpful.

Thank you