Zeldris having Destroyer is fine, but this isn't an example.
Who says the handle counts? Lancelot literally says
the blade is enhanced. No blade on the sword, ergo no enchantment.
How would that even work when 99% of the weapon isn't that tiny part of the hilt that the darkness covers?
King's AP and durability shouldn't be 1:1 with Albion's AP. He was overpowered, severely damaged, and marred his knuckles just by punching Howzer. Also, King couldn't harm either Albion or Hendrickson to any degree.
Spirit Spear is >> Albion's Full Counter, and far more powerful than King normally. So it's not really a factor here.