I've realised that my #RustLan problem isn't #Handlebars_rs but that I need to work with #Axum to set the Response content type. So that is leading me to both Axum State and intoResponse.
Starting to dream about exciting projects that #Rust is going to be great for.
While the strict compiler, types and syntax give a steep learning curve I like the feeling of confidence that they give once you get past them. Fewer runtime surprises.