pretty sure you can auto level the kaer morhen armour using the debug console -
additem('Autogen Armor')
hope that satifies your needs for now
as for the decision -- it is kinda weird because that armour technologically speaking ought to be invented in a few centuries time, if this is indeed the 1200s~ like our world. so imho it and designs like it ought to be a high level end-game armourset.
But I actually hope the last dlc will be something to do with Kaer Morhen armor upgrading. Cape included.
Also... I just don't understand how come this armor is a low level thing. It's a trademark outfit for Geralt judging by all promotional material that's featuring it.