I tried the free terminal app a-Shell that runs on iPhone and iPad; it can run CLI tools like Python and yt-dlp and also works with Shortcuts

GIGAZINE highlighted a-Shell, a free terminal app for iPhone and iPad that brings a Unix-like environment to iOS.

The app includes Python out of the box, and the article confirmed that yt-dlp can be installed via pip and used to download videos.

Downloads are saved in the Files app’s a-Shell folder, and MP4 output can be chosen for playable files.

The piece also noted a-Shell mini, a lighter version designed to use less storage.