1, 
Don't know since when the "Smart/Force Resample" vanished and in replacement the "Frame Blending" established. 
It means that old smart is not smart at all; but the new blending method gives me a huge improment for my interlaced source materials. 
2, 
I do 4k60p (HDR10) videos no matter what source materials they are come from; I rarely use any kind of resample so it's disabled in the project settings. Some times I activate it at event level trying for a smooth motion (which is seldom achievable).
3, 
And so my interlaced materials. All of them suffer whether ghost-images by BlendFields or jitter-motion with half resolutions by InterpolateFields/SmartAdaptive what's ever, and the "Frame Blending" makes it even worse. 
It seems no way but just keep bearing the pain. 
4, 
And it suddenly attracts my attention: Why do I do the doubled sin?
If I select "None" to deinterlace and choose "Frame Blend" at event level, will it blend the fields, too? Another kind of frame - in fact a half frame. 

Here's the result:
Deinterlace=None


Deinterlace=None, plus Frame Blend. Rendertest confirmed it's smooth and clean!

5,
So, if your project is double framerate, you can follow this tip of mine.