Reactive UIs with unidirectional data binding (very important) seem to be the sweet spot. Spreadshees, which pioneered it in consumer software, still reign supreme.

React is quite fast, and is very compact (preact is half the sizef htmx). It seems to be the sweet spot for making rich web UIs.

In the end, this all was a red herring. The problem was in CoreSVG taking 1400ms to render an emoji, clearly a regression. A tweet would suffice to communicate this nugget, but for some reason the author wrote a long and winding piece.