I’ve dabbled with screen location to world space, and it has…weird effects (at least at my little understanding of it all). If I replicate your steps exactly (with a slight twist of just plugging in the XYZ and using the Y coordinate of the player) then pass that on to a Draw Debug Sphere at the center being those values, it just hovers at my player’s location, moving only slightly (I’m guessing a +/- ratio relating to its position on the screen space).
I also tried Deproject Screen to World with this attempt below, but it garnered the exact same reaction.
