Judging off of your code, if you want your character to face aimatt.WorldPosition, here is what you could do:
local hPos = char.HumanoidRootPart.Position
local aPos = aimatt.WorldPosition
char.HumanoidRootPart.CFrame = CFrame.lookAt(hPos, Vector3.new(aPos.X, hPos.Y, aPos.Z))
Basically, this code will make the HumanoidRootPart face the target position on the X and Z axes (left/right, forward/back), and the HumanoidRootPart’s position on the Y axis, so that it does not face up or downwards towards the target.
Hopefully this helps. Let me know if you had any other questions!