Worldbuilding. One of my favorite topics. As fiction writers, we get to make up our own world (setting). We even get to make up our own rules for this world, especially if we write fantasy and science fiction.
In social settings, we're admonished not to talk about religion and politics. Not so in our "world." In fact, those two topics can lead to great plot points. Both could lead to war, not just in fiction but real life, too. But let's stick to fiction.
Just think about the books already written where religion played a huge part of the plot. Did it keep the protagonists apart? Draw them together?
I'm often amazed when I read stories that include a feminine deity. Veronica Scott's Badari Warrior series comes to mind. Considering I grew up with a male deity, no wonder I was surprised. (Side note: in the services I currently attend, our deity is non-gender, referred to as Holy One.)
Whether male, female, or non-gender, a deity can play a minor or major role in our fiction. Even a small part such as an expression: by the Matriarch; Sweet Divinity. Or such a large role that religion could be considered a character.
In my Outer Rim series, the characters come from different planets. It makes sense that each planet would have its own government, customs, and religions. That shows up in little ways, like their expressions. I haven't used religion as a stumbling block to a relationship. Yet.
Could religion play a part in your story?