Christian wrote: “I can not explain how Nibbana can be just Nibbana without consciousness etc. but this is how it is.”
What needs to be explained is how to get to Nibbana.
By the way, one cannot experience ultimate Nibbana (the status after Parinibbana) without getting to Nirodha Samapatti. Are you saying that you can get to Nirodha Samapatti?