A forum member used some pre-painted photo etched 'blurred' props, which go under the name of 'Prop Blur' or something similar. They look OK in photos, as that's the only time you'll see blurred, individual prop blades, but personally, I think they look silly otherwise.
Clear discs look passable, but again, they're not totally convincing, although I admit to using them once or twice in the past, for 'in flight' displays. Don't bother to try to paint the prop blur as individual blades - as mentioned, the only time these ar ever seen is in still photographs, where the camera shutter speed 'freezes' the prop.
If you really want to add some 'movement', then an overall, very thin, misted tint would look better, just to give the impression of the complete prop disc, rather than a clear disc.
It's all down to personal choice of course, but on those rare occasions when I model a spinning prop, I just omit the prop blades and, if a spinner is involved, fill in the holes where the blades would be, and paint the complete spinner.
Unfortunately, in modelling, there are some limits, and portraying movement of any kind, such as props, smoke, etc, is one of these areas.