Are you looking to take a provider with you, or find a provider while in Spain? You’ll likely yield wildly different results of availability and selection because of that, so it’s something important to note.
Beyond that, if you’re looking for a provider to take with you, consider that there aren’t a lot of trans women that have passports in general, and even fewer providers that do. So if it’s a plan on taking someone with, I’d start off by canvassing to find out who has a passport.
As far as a “passive” provider, I’m assuming you’re meaning one that you can fuck, not one that’s going to fuck you. So that may be something to look at in reviews. Which providers are tops, which ones are bottoms, and which ones are versatile, and which ones are versatile but skew more toward one side or the other.
If “passive” means a more introverted/shy/submissive provider, I’m going to have to break your bubble. In this profession they simply don’t exist, at least in a professional setting. Those that fit that bill get eaten alive and quickly burnt-out. They give an inch, an you guys take a mile; only the strong survive here. Any provider worth the money you’re paying her is going to be an alpha, even if she plays the part of that passive schoolgirl type.
You’d be better off looking for a provider that’s capable of playing the part your looking for. There are dozens of girls that are quite capable of that, myself included, that you can find here.