Since mpv 0.34 it even looks for yt-dlp first, and fallback to youtube-dl otherwise. Before that you had to set an option, or just symlink youtube-dl to yt-dlp.
mpv packages in linux distros seem to be pulling in yt-dlp now too; at least on OpenSUSE Tumbleweed, the mpv package recommends yt-dlp and not youtube-dl.
On one hand I'm sad to see youtube-dl's demise. But its prompt replacement gives me hope for the strength of the community to overcome whatever challenges the IP industry might present.
What option?