You don't need JSONB for this - doing this with plain JSON is simpler and already faster than individual inserts for most bindings in my experience.

I typically do bulk inserts using a single JSON argument like this:

    WITH ins AS (SELECT e.value ->> 'id', e.value ->> 'name', e.value ->> 'age' FROM json_each(?) e)
    INSERT INTO data (id, name, age)
    SELECT * FROM ins

The same approach can be used for bulk updates and deletes as well.