A 960 is very slightly better than a 1050 Ti, but still a downgrade, or at the very least a sideways-grade.
Get monitoring software.
Check per core CPU usage and GPU usage.
whichever usage is higher tells you where you need to upgrade more.
If a game is poorly optimized its more than likely going to be a CPU thing.
For example. When I first built a system I only played WoW and I didn't know this.
I had a 3770k and a 650 Ti. WoW didn't run that well so I got a 1080. going from a 650 Ti to a 1080 is a 5-fold difference. I literally only got 20 more fps. Since then I have gotten a 6700k and overclocked it, and I am now about double the fps on WoW.
So poorly optimized games the CPU would be more bang for your buck than a GPU.