Loading of modules can be managed by Webpack's chunk configuration. Each import declaration can be turned into a promise that executes your code when all dependencies are fetched.
I think the react dev team is currently working on an official async loading pattern for a future update. But currently webpack, rollup, etc. offer dynamic import, code-splitting, tree-shaking
I don't have any issues with async loading. I'm just saying that I believe what you are referring to when you say the React team is working on an official async pattern is not actually async loading, but async rendering.
At least every time one of their members said the word async in the last couple of weeks/months, it's what they referred to, and it's a completely different (and unrelated) thing. I can't read your mind though, so I'm just guessing.