The only thing worse than the presence of potential threats is an illusion of security. Now people will think: "I blocked calls from abroad, which means that the enemy's intelligence services or other attackers will not call me, so this is definitely a call from the security service of the central bank."
Better to teach people basic information science. But it sounds too simple and too many people have said it. You won't be able to stand out. And there is no understanding of how to implement this, because it is likely that the initiators themselves understand this superficially.