How to: OP MC. Answer: You don't

The title is the answer, Bye...

...

JK

But actually the title is correct indeed. You Just don't.

One of the things I hate the most in the novels I read is the classic OverPowered Main Character.

Why? Simple. It's Just boring, like really boring. It's indeed really funny seeing a loser getting Op Powers shoved in his ass while being so arrogant about a Power that's not Even his! (I see you Haremgodz)

The MC Just doesn't have any threat. He is so strong that no one can defeat him, everything goes well and yay happy ending. Honestly, Just like the title you don't!

When writing a story with a really powerful MC you have three paths to follow, at least in My opinion

1st: One punch Man style. The story is focused on the side characters rather than the MC himself because he is Just so OP that Even himself feels bored.

2st: The generic way. The MC is Just soooo strong... He defeats every single one of his opponents easily, his friends and harém (or Love interest) are Just there to cheer for him and say How badass he is. The MC usually gets Broken cheats shoved in his ass and still behaves like he is some sort of God. Honestly I can Just clap My hands.

3st: The Protagonist is OP but so are his Opponents! Rather than having an easy path on his journey the MC has to fight beings that are equally strong as him or maybe Even more powerful. One can feel their blood boil with excitment. A fight between two tyrannic emperors and their gigantic empires??! I'm sold!

One of the things I don't like when Reading isekai and tensei stories is the cheats! It makes the MC's journey really easy and kinda removes the Character development, not only that but It Just destroys your World building. I saw a lot of fan-fics where the MC gets so powerful there isn't anything that can threaten him anymore, thus ending your story since there is no point in going forward anymore. There are only few stories with OP MCs that doesn't suck.

My suggestion would be going for path number 3. The Protagonist is strong indeed but his opponents can at least put up a fight thus not making your story boring and useless.

Hope this helps!