Darker gear is often preferred for "stealth" looks or to match dark-themed builds using materials like Deepslate or Obsidian .
Use another Netherite Ingot as the color palette on a different armor piece to add dark, shadowy highlights . Netherite Ingot – Minecraft Wiki Dark Netherite
If you are playing vanilla, the closest you can get to "Dark Netherite" without mods is through the : Darker gear is often preferred for "stealth" looks