600 chapters in and still just the same person as chapter 1. That's what the RAW discussion people are saying.
The MC is an engineer and politician, he will never be leading from the front lines or punching holes in mountains like a Xuanhuan protagonist. His strengths lie in his inventiveness, knowledge and organizational skills. The story is about how he founds and builds a kingdom, not how he punches every problem in the face so hard it explodes into more problems.
It varies in what sense of OP. If it's his personal physique or capacity, then so far, not really. If its just Knowledge, then everything from his previous life is quite OP.
MC is already OP. His IQ is 200000000000000000. All his witches are also OP. Their IQ's are 1000000000000. MC was just supposed to be an engineer, and engineers only have deep knowledge about their specific subjects, but, like Nie Li and Yan Zhaoge, this MC knows everything. Everybody else in the world only has IQ of 100 or 120 at most. This could have been a interesting novel, if it weren't for that fact that MC and his witches are way too OP.
In the real world, no. He's still a regular human so far. Spoiler However, after his battle with Zero (the witch Pope), his mind would enter a dreamscape/memory world every time he sleeps. He is starting to get some superhuman powers like inhuman strength and so on, although the power is only usable while he's in the dreamland. There's very little information on how the dreamland came to be and why he is developing such powers, but so far certain events that happened seem to hint that the power might have something to do with the spherical "God" that Zero saw in Hermes. I'd imagine his struggle against the demons/demonic beasts, and perhaps ultimately "God" itself would need him to perform well on both fronts: using wisdom, iron and fire in the real world, and using his newfound powers (spiritual? physical?) in the dreamscape.