Bhikkhu Bodhi, in his essay “Nibbana” (https://www.dhammatalks.net/Books16/Bhikkhu_Bodhi-Nibbana.pdf), wrote (bold typeface added):
"Nibbana is an existing reality
Regarding the nature of Nibbana, the question is often asked: Does Nibbana signify only extinction of the defilements and liberation from samsara or does it signify some reality existing in itself? Nibbana is not only the destruction of defilements and the end of samsara but a reality transcendent to the entire world of mundane experience, a reality transcendent to all the realms of phenomenal existence.
The Buddha refers to Nibbana as a ‘dhamma’. For example, he says "of all dhammas, conditioned or unconditioned, the most excellent dhamma, the supreme dhamma is, Nibbana". ‘Dhamma’ signifies actual realities, the existing realities as opposed to conceptual things. "
“…it is an actuality, and the Buddha refers to Nibbana as an unconditioned Dhamma.”
“The Buddha also refers to Nibbana as an ‘ayatana’. This means realm, plane or sphere.”
“The Buddha also refers to Nibbana as a ‘dhatu,’ an element, the ‘deathless element’
“The Buddha also refers to Nibbana as a ‘state’ (pada), as ‘amatapada’ - the deathless state - or ‘accutapada’, the imperishable state.”
"So all these terms, considered as a whole, clearly establish that Nibbana is an actual
reality and not the mere destruction of defilements or the cessation of existence. "
So – I’m not taking a stand here but raise these points as they contrast with a number of points offered by other well-respected and knowledgeable Venerables about nibbana – at least parinibbana – being utter extinguishment (not of an underlying Self or self, of course).
It’s been described on this forum as (paraphrasing), “…not even nothing.”
And finally – Ven. Bodhi wrote that parinibbāna does not point to nibbana after death, but to the process of the dying of arahant. Interesting point…
I incline to one of these these “views”, but anyone want to offer further input on this?