This is why I can't finish this PR actually, `Instantiator` needs to come from the DIC and can't be initialized inside the construct method because we need the DIC to inject a denormalizer inside it.  In the last PR, I rewrote the `setDenormalizer` method to make this behavior, but this is totaly not good ~ (see your comment there https://github.com/symfony/symfony/pull/30956/files#r380091247)  If you have any idea how I can solve this issue feel free to help here :+1: 