A big part of the problem is that the surfaces in your file don’t fit together very well. The tips of the surfaces that you want to round off with a fillet are .139 mm apart while your tolerance is .001 mm.
However a fillet can help with the inaccuracy of your model because it will cut off the inaccurate part. But you need a fillet a little larger than 0.5mm to cut off all the inaccurate part.
In the enclosed file I used a fillet of .8mm. and set the tolerance to .01mm to keep the surfaces from becoming more dense than they need to be.
Heli.3dm (362.1 KB)
Another problem with filleting is the singularity at the tip of the wing. You need two surfaces to make a fillet - you can;t fillet between parts if one surface and the singularity is likely to make filleting difficult so I used a sweep2 to round the edge near the tip.
Here is another filleting solution that makes a little more fluid connection between wing and fuselage. See if you can figure out how that was made.
Heli2.3dm (365.8 KB)