So, I bet some of you have encountered the sudden and random low speeds coming out of youtube-dl as of late. Turns out, it wasn’t cause of some peering or server issue, it’s purely yet another undocumented change in youtube causing throttling for youtube-dl:
https://github.com/ytdl-org/youtube-dl/issues/29326
Luckily a solution exists if you use the yt-dlp fork:
yt-dlp [youtube_url] --extractor-args youtube:player_client=android --throttled-rate 100K