It’s hard to definitively categorize sci-fi into an individual box. Unlike other genres, there is never a singular concept that sci-fi focuses on. Rather, it imagines scenarios in which humanity is unbounded from limits on technological innovation and advancement. Thus, the possibilities are virtually endless. In these movies, dystopian futures are a reality, the universe is explored to its greatest ends, and extraterrestrial life is prominent. Even with unlimited potential, it seems like the most famous sci-fi works typically implement a pessimistic perspective.

https://screenrant.com/sci-fi-movies-feel-good-endings-list/