Cpu sets fps limit. Gpu controls resolution and settings. Resolution doesn't affect the cpu at all, it pre-renders the game code, sends it to the gpu. Gpu paints the picture.
If a cpu was capable of 200fps, sends it to a 2080 at 1080p, you'll get that 200fps and the gpu is barely working hard at all. Cpu capped at 200fps, gpu capable of more.
Same setup at 1440p, that's 1.7x as many pixels as 1080p, so gpu now breaking a sweat to get 150fps. Cpu still capable of 200fps, gpu not.
Same setup at 4k, that's 4x 1080p, gpu burning up to get 60fps on screen, cpu still capable of 200fps but is now on a smoke break waiting on the gpu.
None of that is an actual bottleneck, both gpu and cpu working as intended. If anything is a bottleneck, it's the game in question, Anthem being hard on a pc, cs:go not at all.