Stop worrying about CPU/GPU usage numbers or ratios, it is just a number, and, yes, it will be a high CPU number with only a 4c/8t processor. But as long as your frame rates are acceptable to you, then there is no need to upgrade until YOU feel it is necessary. (As long as you have a 2080, cranking up res and details as high as possible with shift some workload to the GPU, but, naturally, the 7700K is not going to be as fast (especially at 1080P) as even an 8700K, much less the 9700K or 9900K, with only half the core/thread count of the 9900K. (The 7700K can't saturate/nax out a 2080, certainly not at only 1440P)
My own 7700K still feels quite snappy on BF1 with a GTX1060, but, then I'm only playing 1080P at 60 Hz refresh..but, there are certainly no stutters, lags, etc...