People don't listen to me but I'm a big advocate about catches and symbols.
That's part of the research. So maybe cold iron is the catch (+2), you can get it anywhere
But maybe how to implement that catch is more rare than just smacking them with it (+0) research.
The same with Love. Even if you could get True Love anywhere, how so you weaponize it? This is part of the research aspect of the catch. Since "symbols" of true love are a catch, symbolism is going to be a big part in how to weaponize it.
Maybe you need to have 2 wedding rings from a couple who've been married for 50 years crafted into the hilt of the sword. So while the sword itself isn't "true love", by the fashion it was crafted and the symbols placed in it makes fulfill the catch. Maybe someone who has experienced true love must craft a sword themselves to use as a weapon.
I have a character that has a catch of "flowing silk". Wrap a club in silk and voila. It's weaponized. If you want to use something like a sword, a special "prayer or ritual" must be said as the silk is being tied to the weapon. This done, the sword acts as a catch even though the silk, that is wrapped around the hilt, never touches the enemy.