Did this TA in Oct 2022. It was meant to be a trip of a lifetime, and it was. We had five nights at the Hotel Nouvel, a renovated art-nouveau mansion on a pedestrian street.
Doing your homework before makes a huge difference. For example, 1 pm is the vermouth hour.
A guided tour of the Gothic district will give you an understanding of Barcelona's history and charming customs. The Catalan people know who they are. So different from how our culture is in the USA.
Don't try to do too much. There are many rooftop restaurants.
Shopping was wonderful, definitely bring an extra bag!
Consider an excursion in Valencia to see how Paella is prepared and enjoyed.
Having a suite is a worthwhile enhancement, if you can.
There will be things to do on the ship. A ship tour was a highlight. Chef's table was lame. The musicians were exceptional, one of the aspects I enjoyed the most.
A TA is a rare and fleeting opportunity to disconnect from everything and just "be."