Yeah anyone who has even a moderate knowledge of how Denuvo works would understand it's not possible for it to not have a performance impact. Best case is that the game developers put the hooked DRM code in some innocuous place like the credits screen or the games startup display that only gets shown once. Worst case is they are forced to stick the hook on some gameplay critical element like the GUI where it gets run constantly.
For those not in the know, the way Denuvo works is that you take some piece of game code and remove it entirely from the game, then store it at Denuvo's site. When the game authenticates with Denuvo it fetches a signed version of that code that only runs on your PC, periodically it needs to refetch the a new signed and encrypted code package. If the game can not authenticate with Denuvo, then it won't have that piece of code to run. Because it's signed and encrypted to that specific PC, it can't (in theory) be stolen and decrypted to be used to crack the game. The issue comes with how terribly optimized these code pieces are and how the game has to constantly decrypt them prior to execution. The Denuvo library will not let the game store the code in memory in unencrypted state it needs to be decrypted every time it's called. If it's a rarely called peice of code, then not a big deal, Denuvo best practices are to use something critical like some visual element on the play screen that then needs to be constantly decrypted prior to being run.