Copy document from website to proton drive directly.
Instead of transferring from this computer ("uploading") to Proton Drive, how about transferring from another computer to Proton Drive?
That is, allow providing a URL to a document so it can be transferred from some other computer to Proton Drive.
I have a personal website and would like to transfer a copy of a couple files without "downloading" them first. Less transferring (less network traffic) that way. Ideally, the transfer request would not come from my computer, but instead from the Proton Drive server (or whatever other computer you all want to use that is in your control for security).
Transferred only once seems more secure than transferred twice (once from website to computer, then from computer to Proton Drive). No need to rely on the computer (f.e. a public computer in a library) to be secure (f.e. not modifying downloaded files, not rerouting a downloaded file, etc.).
And wouldn't the HTTPS request from the Proton Drive server help with securing the transfer directly to Proton Drive? Bypassing the public computer at the library would feel a little more secure, but maybe it isn't really? I don't know. Just an idea.