Is there a way to export all projects to CSV in one go? I don’t want to have to export each project individually as that will take hours
Welcome to the Asana Community Forum @Ben_Andrews!
Have a look into Bridge24 they offer a lot of exporting features: Asana - Export Tasks ans Subtasks to Excel and CSV
The Asana Enterprise plan has an export org feature as well. Otherwise BridgeFlow seems like a good idea like @Andrea_Mayer mentioned. The last one would be to custom code your own export.