Does the Church add new things?
It does not invent: it unfolds what it has received.
The Church cannot change Revelation as though she were its owner. Her mission is to guard, explain, and faithfully pass on what God has revealed.
Developing doctrine is not inventing another faith. It means understanding more deeply what was already contained in the received truth, especially when new questions arise.
That is why the Church can respond to fresh questions without inventing a new faith. She seeks to express with greater clarity the very same truth received from Christ and handed down from the Apostles.
Key idea
Developing is not inventing.
Your challenge for this idea
Distinguish today between superficial novelty and genuine depth in faith.