Gpus don't bottleneck a cpu or vice-versa. Game code and what games you play, thread optimizations, what expected fps, that's what bottlenecks a cpu, resolutions and detail levels are all about the gpu.
The i3 can handle any 4 thread game, the gpu can handle any resolution and any fps. So you could play CS:GO quite comfortably at 4k and still get well beyond its 60fps limits, or at 1440p/144Hz and get consistent 150+fps.
But don't even consider Witcher 3, GTA:V or any of the other 8 thread optimized games or fps is going to tank, nothing to do with the gpu.
Now if you are talking a regular 1080p/60Hz monitor, then an Rx580 or gtx1060 is your best bet as anything higher is wasted.