Try using HasModel instead of ModelEntity. Your best bet at solving this is putting a breakpoint after setting map and having a look at the contents with Xcode's inspector.

Sounds like you might want to change the properties in PhysicsMassProperties for your object when it's in dynamic mode, maybe your impulse isn't big enough.

Since iOS 15 / macOS 12 we can now add shaders in RealityKit 🎉 The entry point for these is GeometryModifier and SurfaceShader. The usage of these is used in the Underwater code sample: Building an Immersive Experience with RealityKit

In RealityKit the animation will always take the shortest path to get to the correct transform. This means that rotations will take the shortest distance. If you want to force the animation to go the other way around you'll have to add two animations in sequence: the first one goes half way round the anticlockwise direction, and the second is the final transform of your entity. This also means that you can't spin around an axis object continually without doing something similar - which is very annoying!!