CPU bottleneck

When using the in game simple performance overlay. The CPU FPS is in the red for me which causes my game to lag and stutter badly. When I start the game., it's smooth but the CPU FPS slowly goes from green to red FPS as I play longer until eventually being unplayable which then I have to restart my game to get the CPU FPS back in the green, it was fine last Friday only, that's the only time the game was smooth for me, every other time, there are always stutters. It's not a CPU usage issue as my task manager shows the usage is below 50%. I added the user.cfg file either way but the issue isn't fixed. My specs are R9 7940H and RTX4070 laptop