Battleroid: I run a 5600X and a 5700XT and I get 35 fps even a low everything at 720p.
It seems it's a game issue.
Happened on a few game before but it's always sad.
I just tested something.
Put everything on ultra and got to game. 30-34 fps.
Staying ingame put everything on low and went back to game. FPS jumped to 94 and 2 seconds later went back to 30-34.
I'm thinking the game is hardlocked to 35 for some reason.
Something is wrong with your system, I suspect. I'm getting better FPS in 1080 (on low, sure) with an i7-6700k and a GTX 970. That's a six year old graphics card and a CPU that is quite a bit behind what you've got. There's no way that should even be visible in your rear view mirror.
Mind you, I had some big framerate problems at one point but the most recent Nvidia drivers did a lot (I think), and making a profile with performance settings in the graphics card driver control panel also gave a few FPS. Going full screen rather than borderless also seemed like it might have given a few fps.
All in all, I can do 60 fps in the apartment (on low, a few fps less on medium) and 30-40 fps while out and about night city.