Is it possible to download m3u8 as separate files using ffmpeg?
Maybe I misunderstood the question.


  Do you want to download each segment in the playlist as an mp4?


if you know the length of time of the segments, you could do** 

ffmpeg -i  'https://example.com/hls/index.m3u8 \
-f segment -segment_time 10  -c copy  -y out%03d.mp4


just match the segment time.