One thing I've noticed is that tropes from tv tropes can really accelerate a relationship's journey, especially in fanfiction where you don't have hundreds of pages or episodes to build things. That 'five times' fic structure, for example. You see 'Five Times Character A Tried to Hide Their Injury and One Time Character B Noticed' everywhere. It basically forces a specific kind of growth—from secrecy and isolation to vulnerability and care—in a neat, reader-friendly package. It's a blueprint, and writers run with it.
Sometimes this feels super satisfying, like getting a concentrated dose of exactly the dynamic you crave. Other times, it can make characters feel like they're on rails, hitting obligatory trope beats instead of making organic choices. The 'enemies to lovers' arc via shared forced proximity during a snowstorm is a classic. It shapes the development by creating an artificial but intense crucible, speeding up the trust-building that might take seasons in canon. It works because we all understand the shorthand.
I guess my ambivalence comes from seeing the same tropes executed with wildly different depth. A skilled writer uses them as a skeleton and adds unique flesh; a less experienced one might just trace the outline and call it a day. The character development ends up feeling either beautifully inevitable or weirdly formulaic, depending.