On a sunny day, just film traffic going by and analyze the picture after. You'll get a feel for how much blur. Look at the metadata and note the exposure time the camera used.
You probably should put camera in Shutter Priority mode ("S") and practice using that and the filters on a sunny day. As meta said above, you need a slow shutter speed, under 1/60 for sure ( the shutter speed is responsible for the blur). On a sunny day, it'll be over-exposed though. Just choose a strong enough filter that allows keeps the image from being overexposed.
There is a "zebra stripe" feature that you can enable that shows "blown out" over-exposed parts of the image. You might consider turning that on. It's in the DJI GO 4 settings, can't remember the name of the option at the moment.