We spent two weeks in the Chania area and loved it. We also loved Naxos and Paros, Santorini not so much, over touristed. But I think Athens is better option for architecture & culture. One day for ancient sites, one day for some museum and some other sites and one day for some more modern sites or markets etc. This is how I'd roughly speaking count the days. A longer visit gives the opportunity to get a grasp of the city, enjoy the sites and some of the museums without rush, get lazy and immerse a bit in the local coffee culture and get to know the place a bit more. Whatever you do, do pick very carefully the place of your stay. If you decide to take a taxi, I would suggest considering https://aktis.taxi/
