Ah this is unfortunate. When using a material with transparency in Reality Composer Pro, entities behind the surface tend to flicker. There is apparently a way to get around this (https://developer.apple.com/documentation/realitykit/modelsortgroupcomponent) but it doesn't appear to impact rendering here. #visionOS
ModelSortGroupComponent | Apple Developer Documentation

A component that allows an entity’s models to be rendered in an explicit order relative to the models of other entities in the same sort group. If this component is on an entity, then it must belong to a sort group.

Apple Developer Documentation
Just realized Blackbox has successfully achieved this effect presumably with RealityKit? So I might just need to investigate further.
@michaelsteeber z-fighting, as I’ve come to learn it’s called, is the bane of our existence. It shows up all over the place. @robertlong or @danfountgames might be able to explain better

@warpling @michaelsteeber @robertlong Hello! This actually isn’t an example of Z fighting, but definitely some sort of annoying depth sorting thing.

In Blackbox we fixed this by making all of our models have ModelSortGroupComponent. The group they reference is the same instance for all of them and the order is set manually for each model. Also the model sort group they all reference can have different depth pass value. We use nil but experiment with which works. Good luck