The setting as romantic resource, not backdrop
Science fiction romance's speculative setting should function as a resource for the love story, generating obstacles and opportunities that no other setting could provide: the alien culture's specific rules about courtship that create friction, the space station's enforced proximity that accelerates intimacy, the political situation that makes these two specific people simultaneously necessary to each other and enemies by circumstance. Writing the setting as romantic resource requires identifying, for each significant worldbuilding element, what it specifically does for the romance: what obstacle it creates, what opportunity it enables, what it reveals about the characters. The setting detail that has no connection to the love story is doing only atmospheric work.