I'm currently playing a game that is a blatent rip-off of Stardew Valley to the point where I frequently question why they were so obvious. (Or maybe those elements are rip-offs of Harvest Moon, I haven't played Harvest Moon to know.) Still, it's enjoyable. The design elements and places where it does diverge from Stardew Valley make it more enjoyable in my opinion.
As the saying goes, "good artists borrow, great artists steal."
Harvest Moon defines the "Turning round a dilapidated farm in a small village where you give everyone gifts all the time" genre. It all comes from there.
EDIT: Stardew Valley has so many QoL improvements over harvest moon though. The early HM games are punishing.
As the saying goes, "good artists borrow, great artists steal."