I will have a go at anicca, dukkha & anatta.
I don’t know if anyone will agree but this is my way of dealing with it by sticking to the middle way and avoiding extreme views. 
There is no pain or sorrow whatsoever in the rupa/arupa loka planes beyond kama loka, but these will eventually come to an end.
And it is this impermanence that makes them dukkha.
But the actual experience while it lasts has no dukkha whatsoever, they are exclusively pleasant.
That is why disciples of The Buddha can remain the entire lifespan of such a plane of existence (millions of years) and then extinguish, unlike others in these planes who die and take rebirth:
”The lifespan of the gods of Brahma’s Host is one eon. An ordinary person stays there until the lifespan of those gods is spent, then they go to hell or the animal realm or the ghost realm. But a disciple of the Buddha stays there until the lifespan of those gods is spent, then they’re extinguished in that very life. This is the difference between a learned noble disciple and an unlearned ordinary person, that is, when there is a place of rebirth.”
”The lifespan of the gods replete with glory is four eons. An ordinary person stays there until the lifespan of those gods is spent, then they go to hell or the animal realm or the ghost realm. But a disciple of the Buddha stays there until the lifespan of those gods is spent, then they’re extinguished in that very life. This is the difference between a learned noble disciple and an unlearned ordinary person, that is, when there is a place of rebirth.”
It is the end (impermanence) of a such experience that makes it dukkha, not the actual experience itself.
And since death leads to rebirth one has to apply not-self to the experience since one is now in a different body and probably will not even remember these past experiences, unless one meditates.
To claim ”there is no self at all” is an extreme view that does not take into account that each and every past life experience is distinct to each other with their own characteristics and experiences, that all had a certain duration.
Yet at the same time all these past, current and future lives are all connected.
There is an actual being right now in the Tusita heaven that will take rebirth later on and become the new Buddha.
So the ”there is only the selfless khandhas”-view is too extreme for me.
It is only a shallow attempt for explaining why
”everything is dukkha”, but it has no depth to it and is not the middle way.
Surely distinctions between beings still has to be made?
”There is mother and father” = right view.
”My parents are actually only selfless khandhas, just like everyone else in existence” 
= extreme view.
The Buddha says we can hardly repay our parents for all they’ve done for us.
This extreme view also downplays the reality of good and evil:
Seeing all as ”selfless khandhas” still doesn’t say if it is a fool or wise person.
So even if one says there is ”only the selfless khandhas” distinctions between ”good and evil”, ”mother and father” ”the future Buddha” and so on, still has to be made.
- How are these distinctions even made by ”the selfless khandhas” in the first place?
Can someone please explain?
One would think and hope it is the self-doer, as found in
”Attakārī Sutta: The Self-Doer (AN 6.38), that makes these distinctions. 
- Is the act of spreading metta all over the world dukkha?
How is this even painful, stressful or unsatisfactory?
Is there a self-doer spreading metta to other self-doers or is it the ”selfless khandhas” spreading metta to other ”selfless khandhas”?
Or maybe self-doers to selfless khandhas or vice versa?
I’m really curious to know.
Maybe better to also study ”Reverse Dependent Origination” and more importantly to stick to the middle way:
“Mister Gotama, does all exist?”
“‘All exists’: this is one extreme, brahmin.”
“Then does all not exist?”
“‘All does not exist’: this is the second extreme.
Avoiding these two extremes, the Realized One teaches by the middle way
Is the ”there is only selfless khandhas” really the middle way?
Isn’t it better say:
-
There is mother and father, there is good and evil and most importantly there is a self-doer.
-
There are distinct previous existences, all different to each other, that one can say belong to this ”very same self-doer”.
So no wonder Sāti the fisherman had the view he had about future lives, if it wasn’t for Dependent Origination everyone would come to the same conclusion just as Sāti did.
- There is a duration when it comes to all conditioned things, this duration can make it seem permanent.
I get it, the reason there even is a ”only selfless khandhas”-view is because ’all feelings etc. are dukkha”.
but please keep the following in mind then:
Even if the wanderer Potaliputta and Venerable Samiddhi disagreed with eachother regarding actions (MN 136).
They both agreed on the following as something The Buddha actually taught:
“Reverend Samiddhi, I have heard and learned this in the presence of the ascetic Gotama: ‘Deeds by way of body and speech are done in vain. Only mental deeds are real.’ And: ‘There is such an attainment where the one who enters it does not feel anything at all.’”
“Don’t say that, Reverend Potaliputta, don’t say that! Don’t misrepresent the Buddha, for misrepresentation of the Buddha is not good. And the Buddha would not say this. But, reverend, there is such an attainment where the one who enters it does not feel anything at all.”
And this attainment where the one who enters it does not feel anything at all is of course Nibbāna:
“Reverends, extinguishment is bliss! Extinguishment is bliss!”
When he said this, Venerable Udāyī said to him, “But Reverend Sāriputta, what’s blissful about it, since nothing is felt?”
“The fact that nothing is felt is precisely what’s blissful about it.
And to top it off so it makes even more sense:
”It’s possible that wanderers of other religions might say, ‘The ascetic Gotama spoke of the cessation of perception and feeling, and he includes it in happiness. What’s up with that?’
When wanderers of other religions say this, you should say to them, ‘Reverends, when the Buddha describes what’s included in happiness, he’s not just referring to pleasant feeling. <——————
The Realized One describes pleasure as included in happiness wherever it is found, and in whatever context.’”
That is why ”Extinguishment is bliss”.
Compared to the goal of the practice (that attainment where nothing is felt) all the planes of existence and the khandhas engagement in these planes are regarded as dukkha, even the 100% blissful ones.
Otherwise one would be content with any of these and not strive further.
And only in that very context can one say ”all is dukkha”.
But ”all is dukkha” is not being said in this context at all by those who take the extreme view of ”there is no self at all”, ”the selfless khandhas”.
Rather this view is only projected on everything and everyone in existence as it was somehow very evident and obvious.
When it is in fact not very evident at all.
It is really quite natural that some meditators come to such conclusions as found in DN 1 and as even Sāti did in MN 38.
Remember that these various views from non-buddhists in DN 1 are not from some kind of speculation on their part, but from actual experiences they have had via meditation of recollecting their past lives in different planes of existence.
And Dependent Origination is also a very deep teaching and not so simple as some might have it:
”Then Venerable Ānanda went up to the Buddha, bowed, sat down to one side, and said to him, “It’s incredible, sir, it’s amazing, in that this dependent origination is deep and appears deep, yet to me it seems as plain as can be.”
“Don’t say that, Ānanda, don’t say that! This dependent origination is deep and appears deep. It is because of not understanding and not penetrating this teaching that this population has become tangled like string, knotted like a ball of thread, and matted like rushes and reeds, and it doesn’t escape the places of loss, the bad places, the underworld, transmigration.”
So that is why I choose to view anicca, dukkha & anatta from this middle way perspective and avoid all extremes.
