Wobbly/shakey steering

About a week ago, I starting noticing this. At first, I thought maybe my wheels needed rebalancing, but that’s not it.

The steering wheel wobbles slightly at all speeds (anything from 2mph-80mph), and it’s wobbling at the same rate as the tires are spinning.

At 60mph and faster, the wobble turns into shaking, the car vibrates enough that’s it’s uncomfortable to drive at that speed.

It’s not accompanied by any unusual noise.

I popped my head out the window and it doesn’t appear that the wheels themselves are doing anything unusual.

What should I look for? I had the whole front suspension rebuilt with new parts 9 months ago, so it’s very unlikely to be control arms or anything like that.