No.
Also, what do you mean?
Versus the wannabe wizards from the short story? Yes. Also, he would walk over most of the foes from the first half of the books.
Harry's been leveling up for almost twenty years.
In the RPG sense, Harry's the adventuring wizard gaining experience MUCH faster than his homebound brothers and sisters.
Anastasia says once that Harry's seen more than most wizards many times his age.
In the game sense? Yes, if he was a player character, maybe not if he was an NPC (especially a antogonist vs. a an RPG party).
Jim knows what's coming and is leveling and equipping Harry for it.
"OP" doesn't mean "A lot of power", it means "So much power it's not fun anymore".
In that sense, we have to trust that Jim is balancing Harry's powers, allies, gear, and item for the foes and challengers coming.

Did the job with Marcone have anything to do with Harry?

Not really. Harry's mentioned at the very end in an almost 'product placement' way. This is not a Harry Dresden story, but it's a very worthwhile read.

Having given this a lot of thought over the years: Harry's an investigator, a wizard. Two occupations that strongly imply a desire -- almost a need to know. To get answers.
Yet, none of the most pressing questions in his life seem to get put on the front burner. For most of the series we see Harry's busy week. The other fifty-one weeks he manages to not learn anything, not talk to anyone about these things.
Why?
Jim doesn't waste ideas, and Mab once removed Harry's memory of fire magic, and his blasting rod. And she did it so smoothly that until he was directly forced to acknowledge it, he never even questioned it.

Personally, I think there's an inhibitor placed in Harry's head that redirects him away from or around these kinds of questions. The person who placed it could have been Lea or Eb or Justin; they all had time and proximity and all of them could justify it to themselves one way or another. Heck, imagine the kind of potent subtle wind magics Justin could weave night after night over months or years.

Anyway, that's my take on the why not part of this...