It can be done without easily, especially if you're focusing on only one or two characters. (Books with huge casts frequently need more meticulous world-building, because you're seeing the world from so many perspectives. Read some recent fantasy (or reread, more likely, amirite?) and highlight every reference to religion you spot. Except for books like the "Percy Jackson" books or the "Queen's Thief" books where the gods walk around and make trouble, there aren't many.

I've been doing a lot of thought on the matter, as I'm going the opposite direction, as my WIP has multiple religions including monotheistic ones, no gods as characters, religious and ethnic tensions, and a main character who considered becoming a member of her religion's clergy before the rest of her life got in the way and is still quite religious. It's whatever works for you, your characters, and your world. Most people won't notice it's gone unless they're looking for it. Curse words, however, will be fun. I suggest sticking to "fuck" and "shit."