I'm curious that you didn't mention Elm here. Did you look at it and decide not, or not look at it?
Elm is awesome! There's nothing quite like it that I know of in its design space to bring user-friendly functional programming to the web. Similar to Svelte, its design holistically packages up the web's languages. Compared to PureScript, it's focused on a small and beginner-friendly feature set, trading general power to optimize for the webapp use cases. Elm has also been influential to a lot of toolmakers!
One important difference with Svelte versus Elm is that Elm makes a clean break from web technologies, while Svelte is designed to work with future versions of the web's languages.