That’s quite a lot of data… We don’t have any premade tool to import all that so you probably need to build something custom. It does not need to be very hard. My recommendation would be to create one document repo per class to give you flexibility at a later stage. Then, create one document (without file) for each file you want to import. A script should be able to do that, reading data from some temporary table where you arrange all the SharePoint data to be found in. Then, once all documents are in place in Docman, you can put the files manually behind a FTP server and/or file shares and use the FTP or Shared repo type. The key then is to get the correct file name on disk into edm_file_tab. The most critical part is keeping track of/syncing/mapping the document that you created in Docman with the file name of the file to be “imported”. It’s not very hard once you understand the structure of the EdmFile, EdmLocation and EdmLocationUser entities. Analyze some existing records there and you will understand how it fits together.
Good luck!