There is not an updated version of that specific sample code, but there are several RealityKit samples available:
"Is the recommended approach to use both RealityKit and SceneKit together to get this to work"
Generally, no you would not use RealityKit and SceneKit together.
Another thing to be aware of, if you are intending to use RealityKit with SwiftUI, you will need to become familiar with UIViewRepresentable. There is a SwiftUI tutorial which explains how to use view representables available here: