I don't see why there is any disconnect. For what it's worth, the "harmony with nature" bit is really just a function of low population, large territory, and minimal infrastructure. "Perfectly beautiful and clean and above mortal concerns" is a perception, elves themselves probably don't regard themselves as such, or if they do, it's a byproduct of other races finding them thus. They are gracile and have refined features, that's just anatomy. As for their mineral wealth and such, they have very long lives in which to accumulate it, and many skills with which to trade for items they don't produce themselves. And as for paragons of holier-than-thou moral virtue, again, I think that's just personal perception.
I think elven societies appear "too perfect" by some standards because every individual is highly trained and highly skilled. There are no elven "commoners" sitting around selling sausages to tourists. Every elf is either a ranger, a wizard, a cleric, a bard, a fighter, or an artisan of some sort. They invest in each individual, and they train their children rigorously. There is tremendous discipline instilled in them by the society as a whole. Those elf individuals who can't fit into this framework naturally leave elf society and become adventurers. But YMMV, if you just don't like elves I can't convince you that my perception of them has any merit.
Actually, the issue is in regard to the resources elves have.
If a society has metal, someone needs to spend their time in the pitch darkness covered with soot and swinging a pick in order to mine that metal, someone needs to stand next to a roaring forge that can heat that metal to a boiling point and someone needs to pound that metal into shape.
If every single last elf without exception is trained to use swords... guess what? CLEARLY they have tons of metal to put towards that end.
Those big flawlessly white ivory towers they live in must be made from stone. And not just any stone, they have been picky about their stone. This means there must be a quarry site, there must be workers with picks and other tools cutting the stone from the quarry site, there must be large numbers of workers dragging that stone from the quarry site all the way up that mountain or into the depths of that forest over rough terrain in order to build these things.
If Elves get to participate in grand feasts every night, then you must in fact have a fairly sizable piece of land that is tilled and worked and watered and harvested constantly.
Someone needs to be doing this labor.
If they have grand libraries filled with books, then someone must be cutting the lumber (even if they don't cut down the tree in its entirety), someone must be working it to pulp, someone must be forming it, someone must be bleaching it... creating paper, particularly with midevil technology, is quite an involved process.
And that goes for the clothing they wear too. For the elves to constantly have the finest in silk clothing despite living in conditions where it would get soiled constantly... you know how much work is involved in making silk in traditional ways? And to cloth their entire population with fresh clothing and cleaning it constantly is tons of hard work.
Look at what you wrote here yourself and if you put a bit more thought into it, you can see the problem. Just
think about it.
Every single elf without exception is a wizard or bard or ranger or craftsman? Every.
single. one?!!
In order for
ANYONE to have that sort of position, to especially have their position dressed and surrounded in the kind of finery they get, it takes 7-9 other people doing the actual filthy, hard, rough, taxing, back-breaking labor in order to build where they live, feed them, cloth them, provide them with their tools, transport all this stuff and generally allow them to live without any distractions from their "enlightened" pursuits that ensure they do not have to do an honest days work in their entire immortal sleepless lives.
Someone must be doing this. And by your own very admission-- it is not a single member of their race. Universally their entire people live as elite nobles with all their cares and worries done away with and all their labor done for them. There are only two possible ways this is possible.
1) They are absolutely exploiting someone else's labor in a way that is morally murky and likely very much a form of slavery or serfdom that they just rationalize away.
2) MUCH MORE DAMNING, they have such extraordinarily powerful magics that they can, with a wave of the hand, eliminate all need for the common class all together... and sinisterly enough, keep this secret to themselves. They have spells that, if used, can provide all the food, shelter, clothing, etc. that a people could ever desire and if they simply shared those spells with the dwarfs, humans, halflings, dragonborn, orcs, hobgoblins, etc... then instantly all suffering people would be able to live in perfect comfort, all pain would be eliminated, all war would instantly come to an end because there would be nothing left to fight over and the 90% of humanoidity suffering across the world would be able to live like nobility and also devote their existences to higher, enlightened pursuits.... Yet they cruelly keep this power to solve all world hunger and strife to themselves while passing judgement on everyone else for not living like saints when they are the only ones who get to live in paradise.
Either way, elves must fundamentally be evil beings if every single one of them can live like nobility when we know for a fact that for anyone to live like nobility, so many more must live like commoners and they are unwilling to provide any sensible explanation as to where their commoners are.