For fresh level-70 characters, the gap between 'build looks good on paper' and 'build actually works' is usually one or two missing Legendary Aspects. Here's the fastest verified way to close that gap this season.
This is the single best repeatable method right now. Run War Plans and prioritize Nightmare Dungeons when they show up as a War Plan activity - it has to come from the War Plan system, not your own Nightmare Sigils, or the trick doesn't work. Once inside, check the dungeon's affixes for Dark Omen. If it's not there, keep cycling War Plan dungeons until you find one that has it.
Push through the dungeon until the Dark Omen ambush boss appears (often the Butcher or a similar ambush encounter), kill it, and loot - on Torment 1 or higher this reliably drops a Legendary item. Critically, do not kill the dungeon's final boss. Instead, teleport to town, hit Reset Dungeons, then teleport back in. The dungeon resets but keeps the same affixes, including Dark Omen, so you can farm the same ambush boss again. Repeating this can produce a Legendary roughly every few minutes.
Legendary items are only half the loop. At the Blacksmith, salvage anything you don't need to keep - this unlocks or upgrades that item's Aspect in your Codex, which you can then imprint onto better gear. Mark obvious junk before you go so salvaging is a bulk action, not a one-by-one chore.
If Aspects aren't the bottleneck, Escalation Nightmare Dungeons are the stronger all-round farm: chain Nightmare Dungeon sigils together in the Horadric Cube and speed-clear them back to back. Each stage's reward portal lets you pick a Gold, Obol, or Material reserve, and the payout scales the deeper into the chain you go.
Sources: MmoGah (Jul 2, 2026) · WebSearch synthesis of AOEAH / MmoExp / GGWTB / NextTier coverage of the same Escalation Nightmare Dungeon mechanic