You can write fiction without dialogue, but what people say and how they say it are such powerful indicators of who they are that to try to write fiction without relying to some extent on dialogue is to deny yourself one of your most useful tools.
Imagine that you’ve got a character whose dialogue has been highly arch and ironic for most of the story, and then suddenly they come out with something very earnest and vulnerable. There’s real power in that shift.
You want to put your characters into positions where they are forced to make choices; those choices will deepen your and the reader’s understanding of the character, and will then shape the events that follow, which will lead to more choices, and more narrative and character development.
An ending that’s good, true, and revelatory usually involves a certain degree of artifice, because in life things don’t actually end.