In the meantime, here's what some fellow Simmers are saying: proposal: The Sims 4 "Goin' Up" pack that is just different ways to physically travel upwards. L and U shaped stairs, spiral stairs ...

You'll figure out a lot of the possibilities by playing with custom stairs yourself, but here are a few examples of the possibilities you can try. You can create a spiral stairwell in The Sims 4 ...

It turns out I've taken a lot of Sims 4 ... of customizable stairs, all sorts of lavish houses became commonplace. Now we can have spiraling stairwells (though still no actual spiral staircases ...