I agree that the Cardinals need a starter if Carlos can't do it, and the thing is they are probably not going to know if he can do it by the time the good starters are off the free-agent market, considering how quickly those guys are moving this year.
So, we agree on the starter.
There should be urgency there.
I'm not urgent about the closer. I'm done being urgent about closers. The Cardinals can move Carlos there if he can't start. The Cardinals have multiple young arms that throw hard who could grow into the role. Signing proven closers on the free-agent market, or even proven relievers, has been a disaster for many teams, including the Cardinals.
Better to let youth figure it out than overpay for security that is misleading due to the volatility of the position, and the vulnerability of the arms who have "proven" they can handle it, and paid the price for doing so.