I think it's not possible to give you any advice based on this information only.. You need to dig deeper.

First of all, be happy that you're a winner! And if you play mid stakes (and I assume you do, you posted this on mid stakes forum), it's not easy to get a high winrate, because there are a lot of good players trying to do the same.

I don't see anything particularly bad in your positional winrates. All are fine, but all of the could be better. Just work on your game, play a lot and improve little step by step. I don't think there's any other way to improve your winrate.

And about your question "where is my leak": you don't have a leak, you have LEAKS. And a lot of them. And we all have a lot of leaks. It's very unlikely that your low winrate is because of this one huge leak that holds you back. It's very likely about several small leaks in your gameplay and your gamesense. Like I said, improve step by step, stop looking for a miracle cure that will boost your winrate immidiately, because the chances are there is no such a thing.

Sure my winrate is about several small leaks, as most of us.
But I still think winrate per position is a good way to think about our game in a different perspective.
SB and BB lossrate : this is a more a defense game.
UTG to BTN winrate : is more an attack game.
So I'm just wondering if the problem is more about "UTG to BTN " or "defense in the blinds" , I mean I've seen somewhere that people say " a normal good reg lossrate in SB is : -20bb/100 and BB: -40bb/100 " If this is true it means that my defense is ok and the problem is more about my "UTG to BTN game" , but Im not even sure about that! about this " normal good reg BIG Bling lossrate is -40bb/100" . I need confirmation from a very good reg winner on 1million+ hands at Mid Stakes , thats why I posted.
Also maybe winrate in postions: UTG, MP, CO, BTN can tell lots of things about "if people play well in a particular position" .

Like for exemple : If a "very good reg 5 or 6bb/100" compare mines winrates and them, he could say yours winrates in SB to MP are ok but CO and BTN are too low ... then problem is mostly about my CO and BTN games, then I could think deeper about those positions, and then questionning about my openning range and flatting range in CO and BTN.
Maybe problem is just a little in UTG and MP, and more in CO and BTN.
Or maybe the contrary, problem is more in UTG and MP , and a little in CO and BTN.