I did Rails for 10 years. This is not even a trade-off anymore. You can write code in a productive language and have it be much less resource intensive out of the box, e.g. Elixir.
Your codebase is as good as your worst developer and it's quite easy to write faulty code in Ruby. The claims of any savings using Ruby are highly dubious in my experience of making lots of money being called in to unf*ck many a Ruby codebase as a contractor.