Noooo, I stand firm on the mysteries one.
Something I love about the crime/mystery drama is that it often hinges on believable characters. You have to buy into the detective, and his particular set of quirks. And you have to buy into the motivations of the characters, because often they behave in irrational ways that have to be explained through intricate personality study.
Romance is ALL about characters. The combination of traits from person X and person Y. If romance was about plot, no one would read it, because romance plots are pretty uniform (sorry) but there are literally endless personalities to encounter, and that's the big draw imo. There will be some books which are formulaic, but I would say there are formulaic books in every genre.
Mystery novels in particular were great for showing me how to handle a lot of elements in SFF. The way in which mysteries are unpacked is very similar to how good worldbuilding is written (as a gradual mystery that unfolds for the reader, rather than an info dump that spoils the suspense). The close character studies were also useful.
I was flipping through some old Jack Vance novels recently. One of them started with 2 straight pages of upfront info dump. No pretense, just HERE IS THE HISTORY UP TILL NOW AND ALSO HOW SOCIETY WORKS, K? followed by story. One thing that really struck me was how slim the novel was; I suspect this is largely down to the fact that he didn't have to twist himself backwards trying to work in that information in a naturalistic way, and simply gallivanted ahead with the story portion of the novel. Otoh, I found the whole info dump very boring, and the novel somewhat lacking in interest compared to some of his other work, so I wasn't exactly enthralled by this approach.
A lot of older SFF does hinge on ideas, but even then the SFF which took care with its characters stood the test of time pretty well, too. (Like Michael Moorcock's "Eternal Champion" stuff and Zelazny's Amber novels.)