Yes, absolutely - as does pretty much every other org in MMA.
The UFC is not a meritocracy, it isn't the equivalent of going from a minor league to a major league.
The UFC is based in USA, thus it has to have fighters that can attract an American audience - just like Rizin in Japan, OneFC in Pan-Asia, KSW in Poland, and logically just about any org based in any demographic would do the same. How popular would an MMA be in Nigeria if it was filled with a bunch of great Russian Samboist? Probably not very popular.
The UFC will then select fighters from other regions (hoping they can find either exciting ones or good ones), because they also have a global expansion in mind, but their primary demographic is USA, with expanding to other markets as a secondary goal.
This is why you might see some really good fighters in Bellator who are from Eastern European backgrounds and wonder why they are not in the UFC (they might also be boring fighters as well).
But yes, the UFC is like any other promotion, and they all take into account where a fighter is from when they are constructing their roster. They also take into account how many wrestlers, grapplers, strikers, and guys with unorthodox bases they have. They also of course have certain preferences to certain weight classes.
Many promotions in other sports do the same thing, hence why when you watch a sport in another country you'll notice a lot of people on the team are from the country of origin.
There is a reason why in sports you see players national flags next to their names.
Just like the NBA has a cap....
The NBA doesn't have a cap. You can have as many players from as many backgrounds.
Unless you mean a salary cap.