Stop being lazy, go back to engineering first principles and it makes little sense to stay with Nix. Guix or any rewrite as a library in a well-developed language* makes more sense.
*For example, why are Haskellians using Nix so much instead of integrating its concepts into their own tooling?
https://github.com/tvlfyi/tvix
To me, the perfect solution would be to have a base like Nix/Tvix you can build on top of, for example to make a package manager for your language, and have the users of that language's PM interact with TOML or JSON.