I was having crazy issues in GDrive and GDocs where I could download nothing using FF - no PDFs, no .docx files, none of my other backed-up files, you'd click download and nothing would happen. Do the same in Chrome, Edge, Safari, Opera, even changing my user-agent to Chrome, and it works flawlessly.
My solution to this problem was move everything off GDrive and into self-hosted options. If Google is going to intentionally hinder usage on non-Google software when no real technical roadblocks exist, I'll gladly use literally anything else.