I kind of like the Elixir Ecto approach where your "DTO"s are mostly plain old data with a single hidden attribute identifying the database table and some other

I kind of like the Elixir Ecto approach where your "DTO"s are mostly plain old data with a single hidden attribute identifying the database table and some other db metadata. They're not live/active, you have to manually pass them to functions to update, but you avoid having two nearly identical types.