I think darutha (disturbance) in this sutta is not exactly a synonym for saṅkhāradukkhatā (or dukkha). Here it is referring to subtle levels of mindstate including the arupa jhanas and leading onto sunnataphala-samapatti, fruition attainment of the arahat. Each different level, although extremely refined and indeed wonderful, is shown to still have subtle drawbacks in comparison to the succeeding. Until finally is described the true sunnata.
Thus, Ananda, this is his genuine, undistorted,
pure descent into voidness, supreme and unsurpassed.
But even here, this unsurpassed voidness, still has the six bases dependent on body and conditioned by life
. So the texts have Sopādisesa nibbānadhatu, the extinction of defilements and the anupādisesa nibbānadhātu .
44. The Nibbana-element {Iti 2.17; Iti 38}
This was said by the Lord…
"Bhikkhus, there are these two Nibbana-elements. What are the two? The Nibbana-element with residue left and the Nibbana-element with no residue left.
"What, bhikkhus, is the Nibbana-element with residue left? Here a bhikkhu is an arahant, one whose taints are destroyed, the holy life fulfilled, who has done what had to be done, laid down the burden, attained the goal, destroyed the fetters of being, completely released through final knowledge. However, his five sense faculties remain unimpaired, by which he still experiences what is agreeable and disagreeable and feels pleasure and pain. It is the extinction of attachment, hate, and delusion in him that is called the Nibbana-element with residue left.
"Now what, bhikkhus, is the Nibbana-element with no residue left? Here a bhikkhu is an arahant… completely released through final knowledge. For him, here in this very life, all that is experienced, not being delighted in, will be extinguished. That, bhikkhus, is called the Nibbana-element with no residue left.
“These, bhikkhus, are the two Nibbana-elements.”