where previously one would have to manually translate the structs to achieve this.
Have you tried https://mholt.github.io/json-to-go? It's obviates the manual translation. Sure, it means you'll have more code in the form of the struct, but that doesn't sound like a concern for you.
If that tool is enough for you?
This does not work in cases where one is forced to use a flat struct. For example, I am using sqlx to scan database columns into a struct, but want to encode the flat structure as nested JSON. Workaround is to manually map columns to nested nested struct members, but being able to tell the JSON encoder to created nested output using tags directly would be very handy.