I'm not sure how keen I am on isekai MCs lately. Being OP doesn't make you a good character. A flaw, something to make them imperfect, makes a good character. Being a fucking idiot, lack of common sense, or a raging pervert do NOT count as flaws, just iffy writing at best.
Inability to feel emotions, detachment from reality, total lack of trust in others, cowardice or insecurity, those are actual flaws.