Is It Really So Hard to Show Off in Another World?

Can you just change this tag whenever you want? The author is pretty casual, after all.

Is this an invincible protagonist story? Though he hides his strength and catches people off guard. Maybe I can't write everyday couple stuff because I've never dated anyone? So I don't plan on pairing him up with anyone for now.

He kills the Demon King with a slap from the start, then is forced to disguise himself as the Demon King to keep the plot going, and outwit his underlings.

Born as a higher-dimensional life-form, Wo Yan is exiled by the Laws to different worlds for various violations. At first, he seeks thrills in each world, or opponents who can give him a satisfying fight. That changes when the Chaos Origin, which opposes the Laws, begins interfering with the normal functioning of different worlds, seeking to lead them all astray and ultimately destroy them. To sort out the threads of fate tangled up by Chaos, Wo Yan sets out on a journey to discover his own purpose. He makes companions who become his allies, gradually becoming an agent of the Laws. Together, they face the calamity apostles spawned by the Chaos Origin in contests of strength and wits across multiple worlds.