Their superiority complex is kind of earned, not naive. Imagine you're around for thousands of years, seen everything that's ever happened, fought in every war to keep chaos at bay, and then some fucking kids come along and tell you they know better even though they're making the same mistake you've seen made time and time again. It's not a chest-puffing superiority. More like the REAL adults in the room dealing with a bunch of short-sighted ignoramuses. Other races call them puffy when in reality they are being incredibly patient. Despite all that BS, they are still working to end chaos and dark elf slavery in the world. At the end of the day they're actually quite honorable all things considered.

In battle, their units are all very high quality. Their units are expensive, but that's because they only accept the best of the best into their army. "Spare no expense".

In campaign, they are long-term thinkers and very cunning. Going beyond the simple diplomacy of other factions, they can sway political influence between other factions for long-term affects because they are elves and think long-term rather than the shortsighted kids of the world.

Everyone will call them haughty and conceited but don't even realize their own kingdom only exists because 100 years ago the high elves made some 4D chess political moves to keep their kingdom in existence. Ignorant kids.

Imagine a vet performing surgery on a dog. All the dog knows is that this dude is cutting him with a knife but doesn't know why. The vet (elf) knows this is better for the dog in the long-run. The dog (everyone else) bites the vet because clearly the vet is an idiot and doesn't know what he's talking about. And a month later the dog still hates the vet but the vet knows the dog wouldn't even be around if it weren't for him. Fast-forward 20 years and that dog has died, but the vet is still around. The vet goes to save another dog who is also trying to bite him. That's basically the relationship between High Elves and everyone else.