Question RTX 2080ti Bottleneck Question...

Definitely a 4690k will be a limiting factor (bottleneck) at that resolution. Quad cores are entry level in many modern games and a cpu like the 4690k can see dips below 60fps in some cpu heavy games. Pairing an entry level cpu with a top end gpu is not well balanced. Agree if at 4K the impact would be greatly reduced but at 1440p the cpu will be a limiting factor.