How do you download multiple plugins vis Command Line?
You can use the plugin/install command for the ./craft cli utility, I'm not sure if you're aware of this:
https://craftcms.com/docs/3.x/console-commands.html#plugin-install
You'll need to know the plugin's handle, but that's all you need. I've never tried specifying multiple plugins in the one command, but that's an easy one to test.
Now, as to why you're needing this is the real question. If you've got your workflow correct, you shouldn't need to be manually downloading/installing plugins with the cli anywhere other than local dev. Project config (if you're using it) and composer should handle all of this. Typically, a basic deployment is as follows:
composer install
./craft migrate/all
./craft project-config/apply

I guess it would help to know why you're downloading and not installing, and in which kind of environment this is happening.