When objects and elements are brought into an existing project via the clipboard, ArchiCAD will allow the unrestricted creation of new layers, line types, fill types, building materials, etc., etc., etc.
Even though it is easier to clean-up extraneous attributes via the delete and replace feature since release 18, it would be helpful to block the event before it happens.
The foreign attributes should be forced to a default, predetermined setting; say ArchiCAD Layer, Solid Line, Air Space Fill, Generic Exterior Material, etc., etc.
Not sure about controlling all the attributes like linetypes but a simple option to place on a selected layer or original layers would help avoid importing unnecessary layers from legacy or 3rd party files.
Apple iMac macOS Monterey / AC26UKI (most recent builds)