Well going by the video I sent, I'd say you need to upgrade the GPU to something like a 1080/1080ti. However, that is only if you don't want any bottleneck, hence getting the best possible FPS. As you saw in the video, even with the setup you posted, the FPS are really good. If you don't want to spend the extra money, there is no need to get the 1080, stay with the 1660 Ti. If you do want to get a 1080, you will need at least a 500w PSU. Remember to go with a trusted brand, and for the GPU do not use power adapters, get a PSU that has all the connectors you need.
The GTX 1660 Ti is a VERY solid GPU.
Paired with your CPU you shouldn't have any issues getting 60 fps at 1080p/60Hz set at Ultra on Most current games.
I get anywhere from 85-120+ fps on current games on Ultra at 1080p with my current rig (see my signature).