A different angle…
The consciousness aggregate can only know and be known when it contacts the other aggregates. For example, we only detect the presence of eye consciousness if there is visual stimuli.
A simple experiment.
Look straight ahead and note what you see. Assuming there is light, you will see a variety of colours. Then close your eyes. You will only see black. Either way, eye consciousness is at work because you sense the presence or absence of light.
Now try to look through the back of your head. Notice that there is no colour there, not even black. Eye consciousness does not arise because the appropriate visual organ does not exist at the back of your head.
This can be extrapolated to all the other kinds of consciousness that sense other aggregates.
If the aggregates fail to arise after death, any consciousness tied up with the aggregates also fails to be arise.
However, that is not to say that there is nothing at all. Just that any consciousness associated with the aggregates doesn’t arise.
The Buddha has sometimes called the deathless a dimension or reality, so Nibbana is not nothingness.
To call something a dimension or reality, one must have been able to experience it. But this is where language breaks down. The experience has nothing to do with the aggregates, so any description of it will be imperfect at best.
I am inclined to go with a consciousness that is not of the aggregates. However, more than a few of my fellow commenters don’t like the idea, as they believe it espouses an eternal ‘self’. However, there is actually no need to superimpose a sense of self onto such a consciousness.
You can read through the debate here if you’re interested. This is my first post on the matter and the debate starts from there…