As a similar, yet more powerful data format I started using Nickel (https://nickel-lang.org). It has very sophisticated typing and transformation features. Highly recommended!
I started working on an implementation in Rust called Woxi (https://github.com/ad-si/Woxi) and I hope to find some contributors, as it is such a gargantuan task!
It will be interesting to see what you did differently!
OCaml is a simpler Haskell, but I don't think it has a C-like syntax. However, rescript[0], the JavaScript like syntax for OCaml based Hindley Milner typed language might actually fit well for small and personal projects.
[0] https://rescript-lang.org/docs/manual/v8.0.0/introduction
But any changes making mainstream languages more functional are highly welcome! It’s just more ergonomic than imperative code.