I can comment only on Civitavecchia. There is nothing there.
I went to Rome on a HAL excursion. It was only OK. It was very physically active, but not rushed. It involved a long bus ride. I hyave noted the availability of services that will pick you up at the port and nget ou back in time. That will involve some research. Look for Rome guides on the net.
My daughter went to the Tuscan tombs and enjoyed the trip, but that would be a challenge for a wheelchair. My wife stayed on board at bthat port.

Thank you Reme

Europe (especially old Europe) is not too wheelchair friendly, sidewalks mostly narrow, and cobble stones.
With that said, most tourist areas are wheel chair "accessible", although their definition is not quite the same as North America.

Here are some suggetsions for your ports. You may have to do some research and see how accessible are they for wheelchair. They are popular attractions and the info should be on the web somewhere.

Las Palmas, Almeria: Alcazaba Castle, Cathedral, Snnto Domingo Monastery

Seville/Cadiz: Granada, Alhambra Palace, Mezquita (Cordoba)

Cagliari: Island of San Pietro, Poetto beach, the Palace

Civitavecchia: nothing there, go to Rome as a day trip

Barcelona: Sagrada Familia, Aquarium, Spanish Vilage

Sorrento: Pompeii, Carpri, Amalfi coast

Funchal: Botanical Garden, the Market

Lisbon: fatima if you are religious, Sintra and Cascais Bay

Good luck!

Thank you, Eschew.