Massive FPS drop after switching to DLSS 4 / Preset K

Hi everyone,

I noticed a massive FPS drop after I followed this guide and used the NVIDIA App to override the DLSS in GZW, switching to DLSS 4 & Preset K.
Before this I was always doing +180 FPS with everything on Epic, DLSS+DLAA, and so on; ofc my fps went down to 140, 120, 100, 90, 70 in places like Midnight Sapphire or Tiger Bay.
I'm playing QHD on a RTX 5080, Ryzen 7 7800X3D, 64 GB DDR5 RAM - and I have the latest NVIDIA drivers because since 0.3.2 they're working perfectly.

Now, my question is: am I doing something wrong? Does my hardware have any problems? Do I need to worry about anything?
Because a friend of mine with a weaker CPU (I think it's a Ryzen 5 5700X3D) is doing far more FPS, like +190/+200 even +240 with the same settings and, most importantly, with DLSS 4 overridden and preset K enabled.

I'd like to hear your opinions and, to help you understand better my situation, I'm leaving a few screenshots of my settings, etc.
(The top and bottom left overlay was set up following the guide I linked earlier).

Thank you in advance!