Arahants don’t need to aim for nibbāna since they have arrived. But desire or not, there’s no avoiding total cessation as all causes for arising have been cut off, eradicated without remainder. Without ignorance, there’s nothing else to arise.
Just by contrasting with total cessation it can be seen that your heart longs for continuing existence in this asankata you are so fond of.
Why do you ask me when I said I haven’t read enough to confidently say that? How about you read everything that is published about Ajahn Chah and then you tell me.
This is why it’s an approximation, for without 6 sense bases, including mind, parinibbāna is beyond concepts and words, but the closest conception we can use is nothing. Seeing nibbāna properly, one should understand the nature of parinibbāna, for those who have wrong views of parinibbāna, it is clear that they have not seen nibbāna, even intellectually. So whatever thing you think of as asankata is not nibbāna, even intellectually, much less experientially.
Parinibbāna is not liable to cease. It is unborn, it doesn’t end, etc. Basically, all that describes nibbāna is able to describe complete cessation without remainder. To conceive a positive ontological version of it as something falls into conflict with the sutta cited above.
I gave you an out, whatever you personally experience and in contact of which you call asankata, that is Dhammakāya, it’s actually a very profound state, but it’s not nibbāna. I suggest you to study this teaching by Burgs properly and thoroughly. So there’s nothing which needs to contradict your personal experiences to arrive at the right view of the nature of parinibbāna as the end of rebirth.
It’s just amazing that this is mirrored on both sides.