The only thing I don't like about Svelte is the reactive blocks, prefixed with $:. There are a number of gotchas, like updating complex objects, which make things a bit...implicit rather than explicit.
I think svelte has taken the best part of the rxjs observable pattern without the PhD level of insanity in the reactive frameworks.
Beyond debouncing and throttling, the uses for rxjs style reactive patterns (all the variations of Subjects) gets super confusing fast. (Look at a moderate sized Angular app and you see the horror of types and brackets needed to handle http calls and errors correctly, for example).
You can even add a line that just says `myVar;` and the reactive block containing it will be executed on every `myVar = ...`.