Remove blur "effect" in Preview when changing pages
In short: Preview cannot be changed. The problem is not one at the application level, but in the way that MacOS's Quartz engines renders images. For some reason, the OS 'sharpens the focus' of the image over half a second or so.

It may be possible to change the parameters of such animated effects for a given application, but it will only be possible in Preview if Apple's developers have included a mechanism to do so within the app. None is documented and it seems unlikely that Apple would go to such trouble.

If you don't like the effect, then leave Feedback for Apple. You may prefer to use another viewing app, but it will have to use different image rendering libraries from those present in MacOS.

(Apropos of nothing, I'm currently writing a replacement app to make up for Preview's shortcomings, and I haven't found any method of changing this animation. Yet.)