Denuvo has no impact on performance. That's a myth. It was removed in DOOM by a patch and it made no difference. The developers of Rime said in their announcement of the Denuvo free version not a word that their release had something to do with a negative impact on the performance. After the removal of Denuvo in Rime I did not hear anything about a changed CPU limit.
Uplay is supposed to encrypt the exe too. How much performance that and VMProtect cost is unknown. At the moment there is no evidence for all these allegations.
Ubisoft can protect its property. Wolfenstein New Colossus was cracked several days before release. That should have caused a considerable damage.
Which site did an article looking at before and after?
I communicated with several good publications about capturing this and they could not do it due to various reasons, in fact this is something I have been keen about for awhile and spoke to them even before the Doom change.
To put it into context, if it had zero impact the studios/publisher would be happy to present this to Eurogamer or one of the other large magazines by inviting them to their location to see it in-house as a performance comparison.
And publications with their tech journalists do visit studios/publishers on invitation so it would not be impossible if the will was there.
Logically, Denuvo MUST have an overhead as it is working on the fly and involving encryption, nothing is for free but like I said how it is interracting these days would be more subtle but we do not know its actual impact on various ways of the game engine.
Remember publishers and developer of Denuvo said even when it was 1st created it had no overhead but they eventually revised/evolved how it worked when there was erratic performance behaviour from certain games with Denuvo.....
Anyway this situation seems even worse here with Assassin's Creed Origins because it looks like it is combining multiple overhead protection programs,algorithms,processes, one of which if done (VMProtect) is pretty much a brute force protection with disregard for consumer and game efficiency/optimisation.
As you say a publisher has the right to protect their investment, but there comes a time when it needs to balance protection and consideration for legit purchasers, especially if it compromises performance or they just use the extra grunt of PCs to add ever more cumbersome protection rather than improve gaming experience.
However all of them should be transparent with such protections and invite publication and tech journalists to analyse at the studio location the game with/without the added protections.
Bear in mind probably most game are developed and early game tested without these protections where they are added quite late in the day.