Athens Greek Ferries Timing Question

Hey I have a flight leaving Athens at 21:20. We are coming from iOS, a 4.5h ferry.

Theres 2 options: ferry arriving at 17:00 and one arriving at 14:00.

Which should we do?

How often are these delayed?

We obviously don’t want to take the earlier ferry and wake up at 7am and walk around Athens for 4-5 hours with our stuff but we are worried about missing our flight due to ferry delays