I upgraded my 5800XT to a 6800XT and got a whopping 10fps increase.
I upgrade my Ryzen 5 1600x to a Ryzen 9 5900X and DOUBLE my frames. Consistently getting over 100FPS
You are probably dealing with CPU bound performance if you are using an older CPU.
Below are my settings. I am playing at 3440x1440 which is 3.5k. I also don't have the game world on an SSD, it's on an HDD right now. But main game files are on SSD. Once I clone my C drive and move it over to the SSD, I'd expect a little bump in performance as well.
