UPDATE:

This was apparently caused by a texture pack I had installed. Deactivated it, and all's well.

I have the RTX Beta on a non-RTX machine. Win10, i9-9900/64GB, 2xGTX1080 in SLI.

1. Load Minecraft
2. Click Play
3. Click Create New
4. Click Create New World
5. Click Create

Minecraft does not leave this screen. All buttons contnue to animate when clicked but have no effect. Pressing Escape has no effect.

If I perform steps 1-4 but press Escape instead of clicking Create, I can exit the Create World screen..