Google is intentionally throttling YouTube videos, slowing down users with ad blockers
(www.windowscentral.com)
I mean, you don't need anything; it'll work with no flags. I have these:
$ cat ~/.config/yt-dlp/config
--embed-subs
--embed-metadata
--embed-chapters
--embed-thumbnail
--sponsorblock-mark=all
$
That'll just embed some useful metadata in the file.