Termux doesn't have youtube-dl or yt-dlp in its package manager. As a result it has to be installed manually.
This script automates the installation of it. It also allows the installation of the daily builds as a separate executable (nyt-dlp).
To install/uninstall
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/RealKasumi/android-installer-for-ytdl/main/multi-install.sh)"