This may get a little winded but I'll try to keep it as short as possible.
As a photographer myself I'm not sure what your intentions with the Mavic are because as an enthusiast you should already know that if you were looking for the best image quality, the
Phantom 4 would have been a better choice at this price point. Now with an Aperature of 2.2 you can't expect the camera/sensor to perform any better than it did in your shot. Most lenses have a sweet spot (where it will perform best in most conditions) and that sweet spot usually falls somewhere between f5.6 - f8. The lack of sharpness is not what first caught my attention in your shot, the over saturation did.
Although a shutter speed of 1/50 of second is good for most handheld applications, you might want to try to bump that up a little higher, especially if you're shooting in broad daylight because that shutter speed could also be contributing to the lack of sharpness you're experiencing. The cars are indeed blurry but so are other parts of this image. That blurriness could a characteristic of the lens but I would lean towards the less than optimal camera settings.
When in post, (because I feel like everything needs a second look before being put on display) how much I sharpen an image depends on where it will be seen. Web sharpening is different from print sharpening which is also dictated by size of the print, etc. The mistake that some people make is; they think they can apply a global adjustment and just be done but it very rarely works that way.
The cars in the upper right are blurry but so are the trees in the upper left and in some spots the tree limbs get mushy. I think you may have to ID the limitations of your tools and make up for those limitations with the other photography skills that you posses. If it makes you feel better, tons of many more expensive lenses fail at the edges, not just the Mavics. If the edges are going to drive you crazy, shoot in DNG, shoot wider and crop.