When uploading a large number of files, don't upload files already present
Specifically for the android app. When you upload a number of files, some of those files may fail to upload properly. When you upload a 2nd time, it may be difficult to see which files failed on the first try. The app should see if there are files to upload and ask what to do. Always overwrite would upload everything whether to was there in the protondrive or not. Never overwrite would only upload files not already on protondrive. Only upload changed files would only upload files that weren't already there, or if already there, did not match in terms of file date or size. This would allow you to eventually upload all files despite failures of individual files.