he got a cross as a gift from some european monarch and he would wear whenever they would meet

No, Rav Ovadia did not wear a cross during meetings with European monarchs. What actually happened is that Rav Ovadia was gifted a cross from the King of Spain - I believe it was from the King of Spain - and he kept it. He did not wear it, he kept it. When Rav Ovadia got sick, some people went to a mekubal who told them that the reason for his illness was because he owns a cross and that he needs to throw it out. They came to Rav Ovadia and told him what the mekubal said. Rav Ovadia, who was himself the biggest mekubal, responded that the mekubal was wrong. According to halacha, owning a cross is permitted because people don't worship those crosses anymore in the way that would make them forbidden idols. He said he would not throw away the cross, and that he would get healthy. And that's exactly what happened - he got better. The halacha is clear on this: a Jew is allowed to own these items because they're not being used for actual idol worship. It's not recommended, but it's not forbidden. Rav Ovadia knew the halacha better than anyone, and he stood by it even when others disagreed.