I made that same assumption for the entirety of the main Witcher 3 storyline, which I played on regular difficulty.
Then I got to the first expansion content, and got my ass handed to me, like, without even coming close to beating the first big bad I encountered in it. And it was then that I discovered that my potion and sword oil game – which I’d been pretty much ignoring, other than heal potions – was NOT up to standards. So I spent about 5-10 hours of game time going back and finding recipes, getting higher level recipes, I think even doing a few quests to get some of the really good oil recipes that I needed.
And I enjoyed that, honestly. A lot.
And I wished I’d played the game one difficulty level harder, because it absolutely would’ve made potions and oils a much bigger part of the experience. (And to be fair: the explanation of the difficulty levels says this very thing, pretty explicitly.)
When this gets its 4k upgrade, I’ll replay it and definitely go that route.