Deciding between Delft and Leiden

I will have ~28 hours to spend in the Netherlands before flying to the US in August. I have not spent any time outside of Amsterdam, and have narrowed down my choices to Leiden, or Delft. My flight leaves at 13:20 the next day. (I am aware that Delft is further from the airport, but that doesn’t really bother me unless there’s something very inconvenient about the journey that I might not know).

I am interested in:
-quintessential Dutch architecture
-cafes/ restaurants
-easy to traverse

I am not really interested in museums, as I will be coming off 3 weeks of travel and would like to relax and enjoy watching the city.

I am very curious about the beaches near Leiden.. are they nice and worth a visit for a day?

Both cities look so beautiful I am having a hard time seeing pros and cons of each. I would love the opinion of people who have been to both/ either!