Crysis 3: Broken Level and Weird FPS drops on Win10x64, GTX 1660S, R5 [email protected], 8GB 3200MHz DDR4

It happens every time if I don't stay to fight the enemies- or if I kill them too quickly and beat psycho to the door. It breaks the scripted event that occurs before Psycho asks Prophet to remotely hack the console to open the locked door. Also weird performance dips, often occurring when nothing demanding is happening. I tried changing CPU affinity, priority, disabling SMT, lowering graphical settings, changing power plans and probably other things I can't remember right now. With high settings, the frame rate can drop from over 120 to below 60 for a second or two even if I'm just walking around- no particle effects on screen or anything. The game is installed to a SSD with 99% health, Nvidia driver ver. 471.4, Windows 10 Home x64 21H1. Incredible how messed up this game is, besides the other two well known performance issues on Windows 10- both of which are fixable. This, on the other hand, appears to be unfixable. Runs with more consistent, predictable performance on my old rig with Windows 7 Ultimate x64, GTX 680 2GB, i7-2600 and 8GB DDR3 1333MHz. In this video, mostly everything is set to low and yet it drops to 55fps in at least one instance.