We've stayed in Athens pre-cruise on a couple of occasions at the Electra Palace Hotel. This was pre-covid of course. It was a very clean, modern and comfortable hotel, well located within short walking distance for local restaurants, shopping, and a longer walk for the Acropolis, etc. Transfer from the airport was by taxi, no booking, just taken from the rank, less than 30 minutes travel I think, and another taxi from the hotel to port, maybe a 20 minute transfer, flagged down by the door porter on the morning. I can't remember the cost of the taxis I'm afraid, but my recollection is that they were quite reasonable.