I'm not sure why people are complaining about a soft image in Log modes? The reason the X3 looks sharper (and I've said this before here) is because in camera processing is adding fake digital edge enhancement. This enhancement makes the image look more "digital" and in fact makes the compression system have to work that much harder, even though to the untrained eye it appears more "detailed and sharp". It is nothing more than an illusion however.
When you record in Log modes you are trying to get as much information from the sensor as possible un untouched, unprocessed form. Although the X5 still highly compresses the picture, the idea behind Log is to get all that contrast information so that it can go through a grading process later, which with skill will allow fine control over the highlight and shadow regions through software like DaVinci Resolve.
In addition to this process, not only to we shoot Log to give us as much as a "film negative" as possible as it were, but in such a process we do not want the camera adding in it's own digital detail enhancement either. Why? Because if we are shooting Log we want a work in progress. During such a process we would ordinarily want detail left alone too so that in our grading software we can add the detail enhancement back in with far more control than we can with the sledge hammer approach of doing it in camera.
In other words your picture looks softer in Log and Cine modes most likely because DJI assumed that if you were filming in such modes you would want the most film like and pliable image possible with stuff like digital edge enhancement left out of the equation because you would be going through a grading process afterwards.
For those complaining about the softness, try putting the picture through DaVinci and dialling the sharpness back in.
