The size of the React and Victory libraries in the demo is close to 800 KB. How can this be reduced? For instance, it took ~12 seconds to render the chart with network and CPU throttling.
No, because there’s a limit on the amount of JavaScript code that low-end devices can process before the user experiences significant delays, and that limit is pretty low. Most of us westerners don’t own these low-end devices, so it’s not easy to test.