A few things I've noticed about cozy romance tropes after reading too many of them:
The small-town setting is load-bearing. It does the work of a hundred pages of backstory. If you say a character grew up in a town with one traffic light and a diner that closes at eight, the reader already knows something about who this person is, what they left behind, and what coming back would cost them. The setting carries the emotional logic so the writer doesn't have to over-explain.
Robyn Carr's Virgin River works because the town has plumbing problems and bad weather and a bar where everyone knows your business even when you'd rather they didn't. The tropes in that series feel organic because the setting has enough friction to make them necessary. A nurse practitioner doesn't move to a remote Northern California town for fun. She moves there because something broke. And the town doesn't fix it on a schedule. It just keeps being a town, and eventually that's enough.
Return-to-hometown is the trope that does the most psychological work for the least setup. A character coming back already has stakes built in. They have history with the place, history with people in it, and a reason they left. The writer doesn't need to manufacture conflict. It's already sitting in the parking lot of the old high school.
Friends-to-lovers slow burn only works when the friendship feels like something the reader would miss if it ended. If you rush past the friendship to get to the longing, you lose the thing that makes the longing matter. The best versions of this trope make you genuinely uncertain whether the characters should risk what they already have.
Most cozy romance tropes are, underneath everything, just excuses to put two people in the same room repeatedly. Forced proximity. Running the same bookshop. Opposite sides of a town committee. The trope provides the proximity. The writer provides the reason it hurts.
Susan Mallery treats tropes like community events. In her Fool's Gold and Happily Inc series, the holiday festival, the town fundraiser, the collective project, these all function as mechanisms that force the characters to interact when they'd rather avoid each other. The trope is sewn into the town's calendar. It recurs whether you're ready for it or not.
Grumpy/sunshine pairs produce more reader investment per page than almost any other combination. I think it's because the reader knows something the grumpy character doesn't yet: that they're going to soften. The anticipation of watching someone's defenses come down slowly, in a way that surprises them, is its own form of tension.
Holiday romance gets dismissed as lightweight, and I get why, but the constraint of a season is genuinely useful. A ticking clock that everybody understands. The leaves change, the decorations go up, and whatever's happening between these two people has to resolve or at least become undeniable before January. Seasons do some of the structural work that plot would otherwise need to handle.