cannot launch apps

This is weird. It looks like your nautilus is launching youtube-dl, which is reporting an error often seen (web search for youtube-dl: error: You must provide at least one URL).

So you would need to report the output of a few diagnostic commands.

$ strace nautilus > ~/strace_nautilus.txt 2>&1
$ strace youtube-dl > ~/strace_youtube-dl.txt 2>&1

Since the output (stdout/stderr) is possibly long, these commands dump it to file. You would post these files in pastebin. Also

$ type nautilus
$ which nautilus
$ ldd $(which nautilus)
$ mkdir -p ~/temp/askubuntu
$ cd ~/temp/askubuntu
$ nautilus "https://www.youtube.com/watch?v=l-dYNttdgl0"
$ youtube-dl "https://www.youtube.com/watch?v=l-dYNttdgl0"
$ ls -al $(which nautilus)
$ uname -a

(see here).

Notes:

1. Avoid "narrating" what you obtained; copy+paste the output.
2. Include from copy+paste also the exact command you entered.)
3. If command ls ... shows a soft link, also post the output of ls <target of the soft link>, and keep doing this if you further get soft links, until you get an actual file as the target.

Related:

1. https://www.tecmint.com/strace-commands-for-troubleshooting-and-debugging-linux/