Is 768k too slow to watch the video from the URL. If not, then I would not call that throttled. Don't need 500 MB/s to watch a video. From what I've seen, when people discuss YouTube throttling online they are referring to max speeds of 60-70k. That's too slow to watch the video from the URL. Not too slow to download, though. And that's why this idea that YouTube is "preventing" downloads doesn't make any sense.

Use this post-data and should get higher speeed, e.g., 1.5 MiB/s. Test it and see if yt-dlp is faster. It shouldn't be.

    {"context": {"client": {"clientName": "ANDROID", "clientVersion": "17.31.35", "androidSdkVersion": 30 }}, "videoId": "$x", "params": "CgIQBg==", "playbackContext": {"contentPlaybackContext": {"html5Preference": "HTML5_PREF_WANTS"}}, "contentCheckOk": true, "racyCheckOk": true}

I do not use curl, except in HN examples. I generally do not download from YouTube. I use the URLs in the JSON to watch the video.