I didn't play MH:World on PC but from what I have seen MH:Wilds suffers from piss-poor optimization that is unrelated to the (two!) DRM they have put in. It may be Denuvo, but from what I've seen, it is just the usual laziness that is prevalent in most AAA games today. Instead of spending the performance budget where it matters by having programmers collaborate with artists, they just throw everything at the engine which ends up overwhelmed and in turn throws everything to DLSS and framegen resulting in an ugly mess (but a raytraced ugly mess!) if you don't have the latest overpriced hardware.
And it may be the same problem with Denuvo. Denuvo doesn't have to cause massive performance problems, but developers have to implement it correctly, using license checks sparingly, and certainly not in performance-critical code.
Also note that when the publisher removes Denuvo, it may also come with other performance optimizations, not everything comes from the removal of Denuvo.