I don’t think that’s actually representative of how demanding a game is, because no game is perfectly paralelized. On my 2700X in Cyberpunk I also never saw any core at 100% utilization, but my framerate was regularly dropping in heavily populated areas with RT on even in 720p when GPU is doing fuck all, simply because CPU cannot feed it RT data fast enough.
I thought Doom Eternal only used RT for reflections and for nothing else. Since it has no dynamic lighting and everything is baked, there is no need for realtime RTGI.
As for RT in general, I consider it very impressive and desirable (compared to nonRT) in Cyberpunk, Control, Metro Exodus, Dying Light 2, Guardians of the Galaxy and Quake 2.
I agree that DLSS is is awesome. Lets me play games in lot higher image quality.