It's not really clear if working DRM increases sales. But most Denuvo games don't get cracked, so it definetly prevents most piracy.

The fact that there currently is no one cracking Denuvo? Empress was the only one cracking and posting new denuvo releases and they've been completely silent for months(possibly over a year? I forget). The only other people cracking denuvo lately are a DRM developerdoing so for the challenge(and not releasing the crack, because they're a DRM dev...) and like one other guy cracking much older versions of denuvo.

Look at when games get cracked, it’s very rarely prior to release

I think most people aren't even aware of the different forms of DRM and whether or not their games use them. For the majority of players, there's no discernible impact to their experience so they have no reason to question any of it.