@Comed1anYou don't seem to understand what I'm trying to explain. Your low GPU usage is caused by the bottleneck of your C P U..
The CPU usage isn't a factor for it to cause the low GPU usage, but rather the CPU's limitation itself.
Search on Youtube benchmarks in BF1 for your configuration and you'll see that everyone else is getting the same CPU usage which scales the GPU one depending on the model of the GPU
Your CPU is causing the GPU to bottleneck.
Higher GPU usage = higher fps
BUT
Higher CPU usage ≠ higher fps, it doesn't work like that. You seem to think that higher CPU usage would make your game run with more fps and it would make your GPU usage higher in the process, but it doesn't work like that. Because CPU usage indicates how stressed is your system, if you reach 100% for example it would cause your system to spike and stutter, and if you have a poor cooling solution it would even make the CPU throttle