Does youtube-dl support downloading from a playlist file, like m3u8, stored locally (with external video resources)?

https://www.reddit.com/r/youtubedl/comments/uz0rzc/download_from_mlbtv/
... to find the m3u8, and to get the "authorization" key. I run a command like:
yt-dlp --verbose --add-header authorization:key_value_here https://hlslive-akc-ewr1.media.mlb.com/hdnts=exp=XXXX/5600K/5600_complete_gdfp2-trimmed.m3u8

There are other m3u8 options I can find when I search through my web browser developer tools, but the results seem to be the same in every case.
It looks like it's downloading, and I end up with a file that is multiple gigabytes. But, when I try to view the file, it looks like it just has the MLB "Commercial break in progress" bumper for the entire video. If I don't add the authorization header, I get an unauthorized message.

I have verbose output here:
https://pastebin.com/mAB8j50y

I have removed my authorization key in the example above, and I have replaced a section of the URL with "XXXX".