GIF is really terrible as a video format. You can upload actual video with sound on Lemmy (most instances use a 20MB, 900-frame limit, also server-side ffmpeg often times out) or Pixelfed (15MB, unknown frame limit).
Yes, I know you didn’t bother to use an AI or commission an artist to sing the new lyrics but you could mux in an instrumental version (or heck, even just leave the original) for me and others who may remember the melody from the radio but don’t associate it with the music video.