It depend on "when" (at which level) you're looking atWhy would you think that npc scaling made the game harder? It didnt, quite the contrary.
NPC scaling made the weak enemies a bit stronger (but they are still pretty weak) and it made the strong enemies weaker (they are now also pretty weak).
I made two full playthroughs before 2.00 (so before NPC scaling was added) and two after, and with NPC scaling the game is noticable easier.
At the beginning of the game until level 30, level scalling make the game easier, sure.
But after level 30, it make the game a bit more difficult (I say a bit, because it still rather easy). Before, there isn't any enemy at higher level than 30/35 on the map. So after reaching level 30, you over-leveled all enemies on the map without any exception and the game turned out to be damn easy, even in "very hard".
I mean before level scaling, beating max level enemies (i.e level 30) at level 40/50 was just a formality... (CDPR had to divide the armor value by almost 10 and remove clothe mods to try to add a bit of difficulty in 1.5/1.6)