So a recent scene in my new favourite fic (I'll plug it every time I can) made me realise one of the reasons I am so drawn to time travel (or in this case age regression) harrydore ( @firendgold this is directed at you. i would have sent you this as an ask but sadly that's not possible from sideblogs ^^)
In canon Albus has power over Harry his entire life; he decides Harry's living situation during his childhood, he largely decides what information Harry gets (concerning Harry's own life) and beyond that, he has power over Harry emotionally (although I don't think he quite realises how much until very late in the game, maybe never)
While Harry has some power over Albus in the last category, Albus is fucking terrified of that fact. He only really let's himself be vulnerable in front of Harry when it's literally his last night on this earth (and at King's Cross if you count that as really being Albus). So he had to be at death's door or fucking beyond it to let himself be even a tiny bit vulnerable.
And here's where time travel (or deaged-albus) harrydore comes in.
Because this particular trope almost always straight up reverses that power dynamic.
Harry is often older than Albus (though not always sometimes they're about the same age). Sometimes Harry is even in a direct position of power over Albus (The Once and Future Headmaster, my beloved). But most importantly, he's always in possession of more knowledge than Albus, about his own life, the future and most importantly about Albus' life.
This tips their canon power dynamic on its head while at the same time giving both of them what they honestly need from each other, both as personal catharsis and to make any kind of relationship between them work.
For his own sake, Harry needs to be able to empower himself visavis Albus, as in he needs to be in a position where he is entirely in charge of his own life and decisions. (This is what already kind of happens in DH ... though honestly, i think due to the book ultimately validating Albus' approach it doesn't go far enough). And for their relationship to work for Harry, he needs to have Albus love him without any pretext. He needs to be sure that he's not just a tool, not just the boy whose destiny happens to be in Albus' hands. He needs Albus to love him for him.
And for Albus, by god, does that man fear vulnerability. And due to the afformentioned reversal of the power dynamic in time travel harrydore, as soon as Albus allows any kind of relationship with Harry, it forces him into it. Harry is the one with more knowledge, Harry is the one with the grand plan (as often this is tied to Harry going back to change the past). Harry is the one who knows Albus inside and out, while often actively concealing parts of himself. The reason why I think this is what Albus needs for personal catharsis, is because it's a continuation of his arch from the book (which was cut short by his death). Here's a man who hasn't allowed himself to be vulnerable, to be under anyone's power in a hundred years. Then comes along this boy who he's suddenly responsibile for. And though he doesn't plan to, he actively works against it in fact, he grows to love that boy. And suddenly there he is, vulnerable once more. It's a beautiful hail-mary and it becomes even more beautiful when, as is the case with timetravel harrydore, the queer undertones are made explicit (and with that I don't mean to imply that Albus' feelings towards Harry are anything other that fatherly in canon. I mean that Albus fear of love and vulnerability is directly tied to his very queer love story with Grindelwald and that him being the celibate elderly gay who is so deep in the closeted he's in Narnia fulfills a common homophobic trope).
And Albus, similarly to Harry, needs this reversal of the power dynamic (in his case this forced vulnerability) for the relationship to work. Because like this, he doesn't have to bare himself, he's already bared. He doesn't have to reveal the worst of himself, the thing he thinks anyone would recoil from. Harry already knows all of it and loves him anyway.
(Yes yes, I'm absolutely imagining very tender dom-sub-sex at this point during which Albus cries his eyes out, while Harry marvels at the fact that he is the one making Albus Dumbledore fall to pieces in his arms)
Anyway, go read the first fic i mentioned (slight spoilers) there's a scene in there that very directly brought me this light bulb moment by having Harry get very hot and bothered about the fact that he has power over Albus Dumbledore ^^
