The american pizza offerings are a bit different in Spain.
Pizza Hut had already exited Spain when I moved here in 2013. 2018 they re-entered the market and it actually tasted identical to UK/USA. They had 4 stores in Barcelona, of which one was 200m from my house. Used to get 1 a week, sometimes 2. Didn't really take off here though so they got rid of nearly all of them after the pandemic. Alas no more...Bye Bye Deep pan pizza.
Dominos is very similar to in the UK, albeit with less toppings available. Probably the biggest American chain now. About 20 stores in Barcelona, and it was barely 6-8 10 years ago. Went here for a year or so after the Hut closed down.
Papa Johns is very similar to the UK menu. I get a pizza from here once every 2 weeks. All 3 of the chains cost the same more or less. ABout 8-9 euros for a collected medium pizza and about 13 for the same delivered.
Used to get my Pizza Hut fix when I visit the UK a couple of times a year. But, slowly, over the last 10 years nearly all the stores in London have closed down. Last trip I had to go all the way to Leicester Square for my fix. £20 for the buffet!!!
rp2000