after getting sick of the constantly changing landscape of webapps designed to do it, i found a plugin for jdownloader that automatically converts the m4a audio files to mp3 and set the filter to only look for audio files. it's been the best solution for stealing music in this modern era where all the kids just use youtube or spotify as their music player. i can use it to download the whole mp4 videos as well, just change the filter to look for video files