I tried various silicon MacBook Pros, and ended up with a refurbished M1 Max with 64GB. I would recommend you prioritize RAM, the more you can afford the better. Also get a big HD, at least 1TB (I wish I had more) because custom builds of UE, compiled, can take up 100s of GB.

@CDNinCA That's super helpful, thanks!! I've been trying for DAYS AND DAYS to ask Apple Support where to get Reality Composer Pro – and all they could tell me was I needed Vision Pro to use it. God I hope you're right and that it's bundled with Xcode 15.1 beta. Regarding animations ... My modeler guy gives me a GLB file (containing GTLF) of a robot which has 3 animations inside, e.g., "WaveHand", "IdleLoop" etc. When I convert that to USDZ, and load in Reality Composer, I can play only 1 of the animations. How can I trigger different ones? Regarding tapping... This same robot model has a few buttons which are part of the same model. In other workflows/apps I would make an invisible "hotspot" which is a 3D shape to capture taps. How can I make taps on different parts of this robot trigger different actions? Thanks again!