Uber?

I was only in Barcelona for an overnight stay earlier this week, but both times I opened the Uber App, it said the ride would be slightly cheaper than a regular taxi, but it would be a half hour wait or more while a taxi was always minutes away. The Uber app can apparently be used to call a taxi. I didn't bother looking at the Bolt app. I ended up getting into the taxi line at the airport and had my hotel call me a cab for the ride back. Both times I had an honest driver who used the meter.

I would use taxis in Spain, Uber is quite limited in many parts of the country and prices are very similar. Taxis are safe, clean, efficient and very affordable.

Taxi.
They're ubiquitous all over the cities, they're easy to book and cheap.

Cabify worked brilliantly for me in Sevilla and Madrid, but it's only available in Alicante, A Coruña, Barcelona, Madrid, Malaga, Marbella, Murcia, Santander, Seville, Valencia and Zaragoza.