About kopis and khopesh again...
I think the khopesh looks far more bizarre than the kopis. Bizarre to me is analogous to orcish.
Thinking pseudo-evolutionary i would prefer it this way:
The valar do know about weapons. They do have knives, spears, bows, maces... All based on tools.
The earliest elf- weapons are imitations of these styles.
When melkor first teaches the elves to make swords these are more kopis- like.. Duilin still uses one of these archaic blades. But feanor them decides to forge a more elegant looking blade- an enlarged xiphos variant. Then the noldor all start to wear this sort of blades and the earlier, more bent models get out of use instead of another, more falchion- like model in addition to the long sword type.
Later as the noldor meet orcs and trolls , and tje ircs are starting to use chain and ring armour too, they move on to more pointed blades closer to arming sword and estoc types, able to pierce scale and splint armor ( or troll hide).
The orcs at first also use kopis- like blades, the way melkor teaches them, but they start modifying them more to their taste and get to more khopesh, bent& sawtoothed types ( or the demons of angband do first) .