The one month one world one year challenge is the most fun one I've ever done. It is pack heavy, but since you only have 4 worlds, you could do Feb - March in Willow Creek, April - June in Oasis Springs, July - Sept in Newcrest and Oct- Dec in Henford on Bagley. It's here:
One Month One World One Year Challenge 2026 | EA Forums - 13045275
You could try a legacy too, there's lots of different variations.
There's also a thread with a bunch of different challenges in it, though it's not been updated in awhile, but you might find something you like there.
https://forums.ea.com/discussions/the-sims-4-creative-corner-en/sims-4-challenge-list-updated-may-24-2021/2272441