hoplon VS electric

What you want to achieve is called Incremental Computations. And clojure have a cool framework https://hoplon.io. And part of that framework is https://github.com/hoplon/javelin library, doing exactly what you want

For non SPA frontend in Clojurescript there is Hoplon for spreadsheet-like dataflow programming: https://hoplon.io/

Interestingly Clojurescript had such a web framework far before Svelte: https://hoplon.io/

Have a look at hoplon: https://github.com/hoplon/hoplon

The cleanest way to handle the backend and frontend charade I've seen until now is using https://github.com/hyperfiddle/electric which is a clojure DSL on top of react

Opa was ahead of its time by at least 10 years. Have you seen Electric Clojure [0]?

[0] https://github.com/hyperfiddle/electric

Scala's ZIO/ZLayer is a great implementation of this idea where the monadic types are visible to userland DSL. Electric Clojure (which I lead) is a Clojure implementation of similar ideas (specialized to web development) where the types are concealed, "just write Clojure". In practice with Electric, we are building really complex/dynamic abstractions (think pure functional app-builder and highly concurrent UI) and we haven't even felt a need to implement multimethods yet. https://github.com/hyperfiddle/electric

I'd expect your auth stuff to mostly just work with some minor jiggling of the middlewares. We have a few out of the box approaches to routing, the tutorials app uses hyperfiddle.router which is an experimental composable router (may be a bit hard to use), the easiest starting point would be a simple goog.history integration. Someone posted a retit integration in the slack iirc. And you can of course roll your own.

Built with Electric Clojure and Missionary! https://github.com/hyperfiddle/electric