I feel like my Geforce RTX 2070 isn't being used to it's full potential, or even 75% of it's potential for that matter. Is it possible that it's my CPU that's bottlenecking the performance of my graphics card, or could it be something else?
You'd have to provide full system specs for us to tell if something else is impacting the 2070...the i5-6400 is part of the issue for sure. On a quad cpu for gaming you'd want to be as close to 5ghz as possible and you'll still be bottlenecked in some scenarios. If you can afford to move to a faster 4c/8t chip it will help a lot.