I am importing BriscCAD 2023 files into Twinmotion through Geometry as a UDATASMITH. Nevetheless, the model is not visible within the Twinmotion interface.
The process you are following is correct, so it will require further investigation of the files BricsCAD file you are working with to see what might be causing the problem.
Since the Datasmith integration inside BricsCAD is developed and maintained by the BricsCAD development team rather than Epic Games, I recommend contacting them for further assistance, but you may also contact Twinmotion Support at https://twinmotionhelp.epicgames.com/s/case-community-page.