I would almost certainly be like a Demon Lord. I'd probably buy myself a really nice cloak and cool mask, then begin to unleash my overpowered abilities to become a god and bring about the creation of a new world. I'll get revenge on the world that oppressed and rejected me. Destroy the societies who cast me out and dismantle human civilization. Along the way, I gain followers and worshippers. The world bows and I become absolute greatness and my magnificent will finally be recognized by all. I'll become the absolute ruler standing above all others. I've watched a lot of anime and epic things so I fantasize about that sort of absolute power.
I'm tired of my life and being alone and rejected at everything in life and being incel and all the suffering I went through. That's why if I was overpowered like in anime, I would unleash my power upon the Earth and take my rightful place above the rest. Loved, respected, feared, idolized, and even worshipped.