Try it first (tested on Rift S)
This project includes a basic set up for an ArchViz material changer system. In the project you can find a blueprint to easily create material changeable objects as well as one blueprint to generate thumbnails at runtime.
NOTE: Use the trigger button on your controller to interact with both the widget and the material changeable objects. If you controller doesn't work make sure to add the controllers keys to the action mappings and axis mappings in the project settings.
DISCLAIMER: This project is not a template or a full product but rather a learning resource.
An example of how a material changer for an ArchViz project could be built.