Curate, connect, and discover
I think i cracked it, the reason everything produced in the times of the High Republic is soo good compared to modern Star Wars, tldr its because of pain.
See, in all the works that date during the High Republic (specifically during George's ownership of SW) there's this fearlessness to show pain and tragedy and death, and i know it sounds like "everything for the children these days is sanitized!" but think for a second if Revenge of the Sith would be something Disney would publish these days and that's your answer, but that's just a tangent meant to emphasize the difference between Og SW and new SW, because what Og SW had was strife, and you the viewer knew that, because every time you booted up KOTOR or played Phantom Menace you knew what was coming, you knew to expect the isle of happiness in which the characters lived to slowly sink beneath the waves of tragedy and you'll see it happen as the characters around the story just dug up their own fates, in very much George Lucas fashion, and THAT is what made the work and the small moments of levity to taste so much sweeter, because you see the characters who you've grown attached to suffer so un-justly that when you return to the good times you can't help but appreciate the good and mourn it's departure.
The reason new SW does not achieve this is because the characters are dealing with the aftermath of the destruction of the baddies, its the birth of the hope for the future, its when you look at the horizon at the END of the movie, yes new problems may arise but the big hurdle is done and Disney didn't cultivate the joy from the Alliance's victory as it should, because instead of giving us proper post-war optimism (as it fits the real life post WW2 countries counterparts and fantasy sci-fi proper) it stuck only with the brooding post-war trauma, and while yes, that is also a very realistic take it still lacked verily from the former and thus there is no reason why we should mourn a character's strife if that is all we've seen from them, its like watching paint dry, nothing particularly changes, just a new villain here and there, the new character discovers new powers, new info, but there is no resolution, no reward for their strife, and even if they were going for a bleak post-war future (which they didn't and it also doesn't fit SW's constant theme of hope for a better future) it still ends up looking incomplete for the mere reason that they don't want to shut the book in case they need to milk the cow some more.
My point with all this was not to bash new SW though, my point was to use it as a comparison to highlight how Og SW built itself on a foundation of hope, how it showed us the height before the fall, how it is possible to make Shakespeare in space and leave all of us with broken hearts and looking hopefully into the future.