i think most WHM trusts have access to cursna however Ingrid is probably most dedicated to cursna but i don't know if she only removes it from the player or other trusts/players too. kupipi's AI has a high focus on removing debuffs so maybe he's quick with cursna as well.
in my experience if curse removal has high priority you'll want to summon multiple trusts with access to cursna to increase the amount of cursnas cast and the chance of successfull removal, unfortunately some/most of your trusts usually fall each doom wave depending on how short the countdown is.
if you want to test trusts performance on doom i suggest popping
revetaur in escha zi'tah, according to the wiki you can force his conal doom move by casting magic of the element of the current ingame day.
make sure to not use weaponskills as they'll trigger his more potent doom move Chthonian Ray, it is more potent and either can't be removed at all or only has a low chance of removal with hallowed water.