Simon E. wrote: The Buddha said clearly that all sentient beings are characterised by Dukkha, Anicca and Anatta..to postulate that sentient beings can evolve beyond Dukkha or solve Dukkha by technology is just as rooted in error as the idea that sentient beings can evolve an atta, or modify the fact of Anicca. Dukkha arises with and from Anatta and Anicca...they can.t somehow be grown out of even with infinite amounts of time. Time itself arises dependently.
So you have been told, and though you have no real direct experience in this regard, you nevertheless keep a good closed mind and parrot the borrowed party line. That's ok, it's what humans typically do, close ranks in the herd. It's an old strategy, based on fear, and characterizes the human animal, accounting for the endless conflicts between tribes of different believers.
As for the Buddhist take, several hundred years after he lived, humans with human agendas began attributing numerous teachings to Buddha, which they eventually put into writing and called sutras, continually adding and subtracting as they felt moved to do so. Some of these writings may have portions that actually bear a faint resemblance to what he taught, while others are more likely representative of the notions of people living at a time when it was commonly believed that the sun traveled around the earth.
Nevertheless, adherents to this or that sub-sect will still argue noisily back and forth with each other about the most obscure elements of the doctored texts, and/or react with condescension and even scorn at the teaching of anyone whom they deem to be outside of their particular scriptural club doctrines -- citing the Buddha’s words for their authority (regardless of whether or not he actually even spoke them, or if he did say something like that, in what context).
Of course, this is typical of religious believers in general. For example, although the Christian Jesus was most likely a composite of several possibly historical as well as certain mythical characters, nevertheless people live and die, and even burn each other at the stake, based on their conditional interpretation of words put into his mouth by a multitude of story tellers who came much later.
After several centuries from the purported birth of the Savior, these tales were carefully edited to serve the political agenda of Constantine after the Council of Nicea, and then tinkered with for several additional centuries, until eventually we get what is today called the official "New Testament".
On the other hand, there are people alive right now who have experienced extended contact with real ETs, and have in turn provided a huge amount of information that is available to study, if one is willing to do the research, rather than resorting to obsolete data and conditioned biases. Among that information, there is the indication that there are indeed species that are not subject to suffering, nor to impermanence (or any concept of time as we humans imagine it), and that in fact the universe itself is nothing like it has been described in primitive human religious literature.
A second, additional body of evidence can be gleaned from numerous nde reports, in which the subjects came back with the imparted knowledge that the universe is teeming with sentient beings, many of whom are evolved far beyond what the human mind can even begin to comprehend.