If your file isn't fully uploading or is uploading slowly, most often this happens because of network speed and connection reliability.
Upload speeds are dependent on the upload internet connection speed and file size, and sadly, we cannot change the speed of the upload on the user's end. For large files on slow connections we recommend exporting to a lighter format such as mp3.
Sometimes internet connections can also have surprisingly slower upload speeds vs. downloads. You can test your upload speed here.
If your upload speed is slower than 50 mbps we would recommend exporting the larges videos and wav files to an mp3 using Quicktime or a similar program and the upload will be much faster, as less data will need to be transferred.