Exactly, the new Google Docs is a great example of how it can can be done, but only by a company with the resources they have.

I have wandered if the solution is to use WASM to take a desktop rich text editor and make it available in the browser within a Canvas element.

No, new Google Docs sucks

For one, extensions that help with translation no longer function because there is no text for them to read.

For two, any language that uses an IME (Chinese, Japanese, Korean, Thai, etcc...) the experience is super subpar

Yeah I'm really interested in seeing something like that, for general purpose. I'd love to see what's possible with WASM + WebGPU for stuff like this.

Yes, and Flutter, the web version, also does it from scratch. Which means CJK sucks on Flutter