This might be an unpopular opinion, I don't know, but I've read fairly often over the years that OP characters aren't fun because "if they're so strong, they can solve every problem without much effort" and, well, I disagree.

I'm not the most articulated person—let alone in English—but I think most people do realize that even a king in an absolute monarchy is just a guy, at the end of the day, and must compose with the people around him to carry his will.

Which means political alliances.

Superman wouldn't far much better. Sure, he's strong. Sure, he could kill or maim or scare anyone in his way. But then what? What happens when people get frightened by him getting rid, one way or another, of anyone in his way? What happens when they refuse to listen to his Objectively Perfect Solution and thus get in the way of making the world better? Does he maim them too? Because that's where his strength lies, in terms of raw power. He's not a billionaire or a king or a god. He's just a really strong guy with the heart in the right place.

And I would argue that a noble in Ishgard has a better chance to make meaningful changes than a random Very Strong Adventurer.

Even if we look at the Warrior of Light, for example, they don't save the world through raw strength alone. Their real strength isn't in their combat abilities, it's in their talent for connecting with others. Killing the Bad Guy (or incapacitating him) only works because the Scions had cleared the path first and made sure that the void left by the disappearance of said Bad Guy will be filled in a way that ensures meaningful change instead of chaos.

Which, again, means political alliances.

So I don't think people should be afraid of playing an OP character, or playing with someone who has an OP character. No matter their raw strength or magical abilities, they're still just A Person. And as such—unless their Mun is really bad at roleplaying—they'll have limitation and weaknesses.