DXR and light baking are not directly related. You can use DXR with light baking, or you can use it without.
DXR light baking is not integrated into the engine yet. DXR light baking will likely depend on UV maps, but we’ll see when it actually comes out.
Baking lighting will always be the better option when it comes to performance, with the downsides of having to bake, using extra storage for lightmaps, etc. But you can always check Force No-Precomputed Lighting" checkbox in “World Settings” and not use baked lighting.