The business apps I work on don't benefit from SSR (having to write components that can render server-side is friction without payoff), and I already have a client-side router that supports nesting.
I'm still using https://github.com/TehShrike/abstract-state-router which I wrote years ago after thinking "ui-router is great, but I need a version that can keep using no matter what component library I want to use in the future"
Also in the process of writing an app that has no ssr needs. There are some minor annoyances with SvelteKit and interested in other options.