You already have that, but it is tied to Building materials, which is the way it should be. Property manager and properties there are applied to entire element. For example wall is composed from several building materials, and they have physical properties.
Values are written in a file called materials.xml, which you can find in Graphisoft/ArchiCAD 21/Addons/Energy Evaluation folder. You can Edit that file and add your materials, but be carefull with formating. Real world valčues you have to obtain from manufacturers of building materials.
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Gorazd Rajh
From AC 6.5 onward, Ryzen 9 5900HS, 48 GB RAM, RTX 3080, Win 11