It seems the Afanche 3D Viewer for Mac also posses the capability for DXF export and thus should be able to export models from Quake game as DXF. However, DXFs contain 2D data so it is not clear whenever this conversion is actually possible or not and what the outcome will look like.
Found 2 different conversion types using the same filename extensions.
Conversion mdl to dxf type 1:
Convert from Flight Simulator 95/98 3D model to AutoCAD DXF Drawing Exchange Format.
Microsoft Windows software - convert mdl to dxf on Windows
A conversion utility for Flight Simulator MDL models
File type (from-> to)
Convert from mdl file format
Flight Simulator 95/98 3D model
AutoCAD DXF Drawing Exchange Format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned mdl to dxf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Conversion mdl to dxf type 2:
Convert from Quake model file to AutoCAD DXF Drawing Exchange Format.
Apple macOS / Mac OS X software - convert mdl to dxf on OS X
A Mac version of the popular 3D visualisation software