I don't understand this question. GPUI's unstable to non-existing a11y, IME, RTL etc. support is well documented.
The way you phrased it, it's not. However if you've used Discord, you know that to render it you're essentially rebuilding a web browser due to the sheer variety of formatting, images, animation, audio, videos, languages, widgets, and whatnot that must all coexist in arbitrary forms in every server/room/forum.