Indeed, I believe I am the "other poster" Salty mentions above; I use Blur Reduction: 10 and Judder Reduction: 5 on my Samsung, and at these levels, it seems there's just enough smoothing so that soap opera effect doesn't kick in (once I hit 6 on Judder, the motion smoothing seems too aggressive, and we get that hyper-surreal movement not really preferred for film content).
The problem I am having -- and one that apparently is never going to be solved -- is that for whatever reason, ever since purchasing, installing and using our newer UHD Blu-ray player, a Panasonic UB9000, motion appears to get seriously tripped up by these settings in the Samsung, causing horrible "ghostly distortion/tearing" during very fast movement in action scenes, notably in the FOREGROUND (in front) motion and most noticeably with 4K Blu-ray content (though it DOES occur with DVD and 1080p Blu-ray content, too). I cannot explain why, ever since replacing the first UHD BD player we owned, a Cambridge Audio CXUHD, these issues have begun with the Panasonic, but I didn't notice them using the Cambridge (or even an old Oppo BDP-83 before that); however, they're clearly present, and when I shut AMP completely off, they disappear. So it's something with the way this Panasonic player is interacting with the Samsung when motion interpolation is engaged.
Some extreme examples of when I notice this include moments on the Bad Boys for Life UHD Blu-ray, when Will Smith and Joe Pantaliano's characters are sitting watching a neighborhood basketball game and whenever the players move quickly in front of them, the screen distorts into a blurry "breakup" that almost looks like bad pixelation. This also happens on the Joker UHD Blu, whenever a Gotham train rushes by the screen, causing the extreme blurry distortion I'm describing.
I thought that maybe it's something in the way that Blur Reduction is interacting with Judder Reduction on their sliders, being that I have been told that at a certain point on these scales, the two "frequencies" the Blur and Judder Reduction are supposed to be affecting begin affecting one another (but I can't confirm that). I don't watch any content outside of 24fps film (so low frame rate) on this HDMI input that uses the AMP settings, so I don't know why Blur Reduction -- which is supposed to work on HIGH FRAME RATE content only -- would come into play here, but is it remotely possible that this high setting of "10" for Blur is somehow messing with the Judder setting?