I tested these during last preview and have a suggestion I feel would give these weapons the desirability necessary for convincing people to farm for them.
Any chance you can swap out an effect on these?
The effect found on these called Soul Eating is nice and deserves a legendary version and you could go as far as to make it 1000 temporary hit points like what is on legendary affirmation, you could also scale up the negative levels from 1d3 to 2d6.
Swapping the cold iron effect with fetters of unreality and making this effect the effect gained from upgrading would make the weapon raid tier, currently it seems to lack the excitement I'd expect from a raid tier weapon.
https://ddowiki.com/page/Item:Grave_Wrappings