Sintra worth visiting?

My husband and I (33 and 32 y/o) visiting Portugal and Spain next year in mid May for 15 days and are trying to put together our itinerary.

We are flying in and out of Porto and know we want to spend some time in the Algarve but are contemplating if a stop in Sintra is worth it? We are interested in the palaces and moorish castle they have but we have a lot of things we want to do so I don’t want to over do it.

We from the US and want to mix some history, culture, and nature on this trip but aren’t necessarily worried about hitting all of the popular places.

In Spain we are focusing on the southwest (Cordoba, Grenada) and in Portugal we were considering Evora or Monseraz and Tavira.

For reference, we went to Italy last year for 2 weeks and did Rome, Venice, Assisi, Ravello and Amalfi town. We really loved everywhere we visited but particularly enjoyed Ravello and wish we stayed there the full 5 nights rather than moving down to Amalfi.