Ah, I'm surprised at the EaseUS and Another Site's statement although I haven't researched well because I didn't need to.
I thought cloning was a sector to sector identical copy including unused sectors so the Macrium Reflect statement makes sense.
I have never resized a partition to a smaller size so I don't know the procedure.
Presumably you would somehow do a "defrag" sort of thing to move all the data to the 'front' part of the disc and then split it into two partitions, one with your data and the other 'spare'.
Good luck.

BTW, I tried to edit my post (to change 256gb to 250gb) but after clicking EDIT it just gave a blank form!!