Good lord, it is really forced.
About the sword breaking easily, is a thin blade type, it needs the right techinue to fight with it and for maintenance.
I presume this work is a novel adaptation and in there the idiot GM took longer to break it, straing the balde in the right spot and it will break, we can even add that is possible that it never got any real maintenance, it can evolve, but not self repair.
We could even push it, like the author did with this plot, and say is more a catalyst for magic or a knight in that world can clad it in mana, so without the right wielder is not super good.
A guild master arrested from the coutnry for breaking a national treasure and firing the best blacksmith in the nation, unless this dude have contacts with dark guilds or was some kind of black ops before doing business I can't see how he could escape.
He already brought up how he fired MC, so can't even backtrack on that.