(ArgumentError) argument error (stdlib) :ets.lookup_element(:hackney_config, :mod_metrics, 2)

No, using :extra_applications like what you are using is what I would recommend.

Ah, I see what’s happening. Normally I’d let Application.ensure_all_started(:faithful_word) start all of the dependencies of your application. But since you’re starting all the dependencies manually you have to add any transitive dependencies (i.e. dependencies of your dependencies) as well.