IT'S FIXED.
So, after opening and removing the fuel level sender and inspecting the inside of the tank, I found this piece lying around in the tank, loose, it turns out that it is part of the vapor line - vent system, from where the fuel vapor goes up into carbon canister and out through the filler neck vent hose.
That was in the fuel, full of fuel, clogged and blocking air from coming out of the tank via vapor canister, that's why the only way possible to put fuel in was by pushing the tank flap open with that long oil stick, letting the vapor come out from there, then holding it open while fuel goes in.
After understanding how and where it is clipped inside of the tank, took me 2 minutes to put it back into position and clipping it again, very simple.
Probably, due to the hit, that came loose, and started that problem, because it clips very easily on the top of the tank.
See below:
Here is the location it clips inside of the tank, you can reach that easily from the opening when the fuel level sender is out.
