Please explain further. it is interesting that you would go to v34 (but why not 35?) because the next is the one saying the Son (thank you Danoh!) did not know when that would happen, that the Father would decide.
I see 34 as the time text. The disciples, out of ignorance, asked Jesus 2 (possibly 3) questions. This verse begins the division between His answers about what will happen during their lifetime and what will happen when the world/universe ends. Verse 35 begins His answer about the end of the world, time and universe. There is a marked change in the language used as you have pointed out.
I have yet to hear a good reason for not taking verse 34 in its most natural and simple sense; that the generation of the disciples is in view. The only reasons I have heard against it include phrases like; "It is obvious that..." or "...what follows sounds like the end of the world to me." But personal opinion, especially my own, is not good enough. So I look to see if the Bible can interpret it without my opinions getting in the way.
I find it quite clear that up to v29 is 1st century Judea without a doubt;
We agree on that. I think that taking it out of the Judean context stretches it beyond the natural meaning.
then 29 says 'right after (the preceding) and goes on to worldwide, end of the world, judgement. End of the universe actually.
Here is where we will disagree.
I don't fault anyone for thinking verse 29 sounds like the end of the world. On the surface it does. But Isaiah predicted the fall of Babylon at the hands of the Medes with exactly the same language. Is 13:10KJV. Egypt was overthrown by Nebechadnezzar and Ezekiel prophesied it with these words. Eze 32:7KJV. It was well established that these phrases spelled disaster for nations being judged by God.
Identifying Israel as the sun, his wife as the moon, and his progeny as stars goes back to the days of Joseph and his dream about his family. I think Jesus was simply using the words of the prophets to predict "lights out" for the nation of Israel. We know that happened in 70 A.D.
When we add to this the biting words of Jesus in chapter 23 and His pronouncement of desolation coming upon the house of Israel (Jacob), I don't have any problem understanding verse 29 in a historical context.
Heaven and earth will pass away. Like Rev 20:11. No time for a kingdom in Israel in any of this. The NHNE are immediately after that judgement, of course.
"Heaven and earth will pass away" is, in my view, Jesus declaring the world will, at some point end, and introducing His explanation of how that event will unfold in stark contrast to the nitty gritty of what will happen during their lifetime.