[2023] first omni ever for me at 270 corruption, good rolls too

The minimum area level required for a unique to drop with LP is 19 less than its effective level for legendary potential. So, a unique 115 effective level for legendary potential, such as Wings of Argentus, can drop with legendary potential as long as you're in a level 96 area or higher.

Using a rune of ascendance always counts as area level 100, so that you don't need to horde them until you find a level 100 area, but has a lower chance of rolling legendary potential compared to dropped items.