If you've been having trouble getting Shadowlands' ray-tracing to kick on, Blizzard's got any help on the official forums. You'll need a GPU that supports ray tracing tier 1.1, with the newest drivers, as well as the May 2020 update for Windows 10 -- and, clearly, you'll need to be using DirectX 12.
As announced earlier this week, the GeForce 452.06 driver offers additional support for your WoW Shadowlands beta. You can head into the Blizzard website to opt-in to get an opportunity at beta accessibility, as always.
The people at Wowhead have caught a load of comparison shots to show what people ray-traced shadows look like. It is a shame WoW ray tracing will not go past shadows for now, because the stylised design and simple character models would appear incredible under the spotlight of extremely realistic lighting.