I don't know what specific issues you're having, but for me I can simply do a select-all in Google Drive, right click and hit Download.

After some time of processing it'll eventually give me a .zip which contains all the documents and files. Google Docs documents are exported as MS Word .docx files. I don't have any spreadsheets to hand, but I believe they're exported as .xlsx format files too.

e: I see Google Takeout also allows you to export these, too in choice of formats: https://takeout.google.com/