Super ability of the Dark Elves. Auto-translated

They won't just not hinder, but they will help. Freezing, shock, armor destruction… We use all the elements at once, and a different skill build in the Chaos Magic branch looks very one-sided.
SA and the set multiply the damage from chains. If the hero has a Master's Amulet, we get +50%, and with SA and the set, it's all +300%, i.e., four times the damage, and with luck, eight times. And if we're lucky and have more than one native city…
Imagine Earth Shock dealing 16k damage – this is quite possible.

I've played this game a lot, and I've never seen damage like that. I think it's impossible to achieve even 4k damage in a normal one-on-one fight.

Can someone explain in simple terms what the absolute ability of the Dark Elves does?

It's very simple: the Warlock's elemental affinity is doubled, meaning their units deal even more damage to opposing elements. For example, +30% damage from skilled, irresistible magic becomes +60%.

While not the absolute best among absolute skills, it has the best requirements, to the point where it doesn't need any adjustments. Consider: "Lucky Sorcerer," "Unstable Mana" with "Secret Knowledge," and all general Chaos magic skills.

I don't quite agree with the idea that the requirements for the Supreme Artifact are ideal.
"Luck" is a race-specific skill, so overall, it's a useful skill.
"Magic Resistance" is debatable. The value of the skill has been slightly reduced due to black dragons and the Warlock's ability to penetrate magic resistance, and the skill was questionable to begin with.
"Soldier" – hmm, the Warlock doesn't have a single unit that could benefit from the Soldier skill. Not a single one, unlike dwarves or humans.
"Lucky Wizard" – well, that's good, yes, the average damage increases by one and a half times and works well with the Arcane Wave spell.
"Wizardry" – everything here is definitely useful, I don't argue.
"Chaos" – but there's no point in maxing out all three Chaos masters at the same time. Depending on which spells you get, you should either focus on the Fire master (up to Pyrokinesis or Fire Fury), or on "Cold" with "Deadly Cold" (and take another Chaos master as well).
But overall, yes, it doesn't look as bad as it does for some other races.

"Soldier's Luck" – hmm, the Academy doesn't have a single unit that could benefit from Soldier's Luck. Not a single one, unlike Gnomes and Humans.

The Witch's whip attack benefits from it. Although it's rarely used and not always to the Witch's advantage. Applying Berserk directly hints at the Witch's inclination towards masochism.)
Otherwise, it seems that only Mages don't have units that need Soldier's Luck.