No, yeah, I get that, I was asking about that “100% CPU usage and 70% GPU usage and if I turn details up I get a slideshow”. Is this at 1440p or are you playing at 1080p?

Edit: actually, I watched some benchmarks and the RX580 should deliver some solid FPS at 1440p so the CPU is the actual bottleneck here. Go first option and that will give you a very big framerate boost

Your monitor is 1440p, are you playing at that resolution?