Maybe since challenges are not your thing, you can focus more on creating stories that you play out. For me, I feel like challenges help generate storylines.
There are also build challenges that you might find interesting (I see in your signature that you like building).
I cannot help but recommend the Build a City Challenge because it's helping me to think differently about how Sims can live while building a town one lot at a time.
Maybe think about what kind of things you normally do in the game, and try to avoid those things specifically and see how else your Sims can live their lives. I've never really played with the Off-the-Grid lot trait, my Sims always have careers, and I generally renovate rather than build lots. With the BACC, I'm playing Off-the-Grid, none of my Sims are in careers, and I'm building everything from the ground up. It's fun because it's a change from the normal things I do in the game.
