Audacity projects (.aup files) might be exported as common MP3 using the Audacity program itself. Otherwise there is no way how a project could be converted to audio, because it usually contains just references, not the actual multimedia file which is kept separate.
Note: It is likely you will also need Lame and FFmpeg libraries installed, if you already do not have it as part of Audacity installation.
Updated: July 3, 2023