Condition Layout and custom product page in React

Hi, I’m diving deep into SKU specifications and variations. I want to create a Condition Layout where, based on the category or specification (color or size), I can build a custom layout.

I read the Documentation and understood the concept, but I’m still unsure how to build this custom page using React, given that the “default” page is built entirely on top of pre-configured standard blocks from the store theme.