Not too difficult to find out, due to games on GoG. There have definitely been some discrepancies with non-protected game performance vs drm, the mentioned Devil May Cry in the video and Mankind Divided had longer load times due to Denuvo, but any significant differences are actually pretty rare.
PC ports exhibiting poor performance are usually far more down to the porting team and/or the game's engine being able to function well on different architectures than just the addition of drm. There's a lot of games without DRM released that would make these headlines a monthly occurrence if so.
